#include<stdio.h>
#include<stdlib.h>
#include<string.h>

typedef struct
{
    char score;/*编号*/
    char name[10];//姓名
    char num[15];//号码
    char email;//邮箱
    char adds[20];//住址
}person;

person pe[80];
int menu_select()
{
    char c;
    do
    {
        system("cls");
        printf("\t\t********通讯录********\n");
        printf("\t\t*                    *\n");
        printf("\t\t*       1.显示       *\n");
        printf("\t\t*       2.查询       *\n");
        printf("\t\t*       3.修改       *\n");
        printf("\t\t*       4.添加       *\n");
        printf("\t\t*       5.删除       *\n");
        printf("\t\t*       6.排序       *\n");
        printf("\t\t*       0.退出       *\n");
        printf("\t\t**********************\n");
        printf("\t\t请您选择(0~6)");
        c=getchar();
    }while(c<'0'||c>'6');
     return(c-'0');
}

int Input(Person per[],int n);
{
    int i=0;
    char sign,x[10];
    while(sign!='n'&&sign!=N)
    {
        printf("\t编号:");
        scanf("\t%d",&per(n+i).score);
        printf("\t姓名:");
        scanf("\t%s",per(n+i).name);
        printf("\t年龄:");
        scanf("\t%s",per(n+i).avg);
        printf("\t电话号码:");
        scanf("\t%s",per[n+i].num);
        printf("\t通讯住址:");
        scanf("\t%s",per[n+i].adds);
        printf("\t电子邮箱:");
        scanf("\t%s",per[n+i].email);
        
        gets(x);
        printf("\n\t是否继续添加？（Y/N）");
        scanf("\t%c",&sign);
        i++;
    }
    return(n+i);
}

void Display(Person per[],int n);
{
    int i;
    printf("-------------------------------------------------\n");//格式
    printf("  编号   姓名   年龄   电话号码   住址    邮箱");
    printf("--------------------------------------------------\n");
    for(i=1;i<n+1;i++)
    {
        printf("%-5d%-8s%-6s%-13s%-15s%-15s",per(i-1).score,per(i-1).name,per(i-1).avg,per[i-1].num,per[i-1].adds,per[i-1].email);
        if(i>1&&i%10==0)
        {
            printf("\t--------------------------------------------\n");
            printf("\t");
            system("pause");
            printf("\t---------------------------------------------\n");
        }
    }
    printf("-------------------------------------------------\n");
    system("pause");
}





int Delete_a_record(Person per[],int n);
{
    char s[20];
    int i=0,j;
    printf("\t请输入想删除记录中的名字:");
    scanf("%s",s);
    while(strcmp(per[i].name,s)!=0&&i<n)
        i++;
    if(i==n)
    {
        printf("\t通讯录中没有此人!\n");
        return(n);
    }
    for(j=i;j<n-1;j++)
    {
        strcpy(per[j].num,per[j+1].num);
        strcpy(per[j].name,per[j+1].name);
        strcpy(per[j].age,per[j+1].age);
        strcpy(per[j].adds,per[j+1].adds);
        strcpy(per[j].email,per[j+1].email);
        per[j].score=per[j+1].score;
    }
    printf("\t\t已经成功删除！\n");
    return(n-1);
}

void Query_a_record(Person per[],int n);
{
    int m;
    printf("\t\n请选择查询方式:\n");
    printf("\t|---------------------|\n");
    printf("\t|     1——姓名       |\n");
    printf("\t|     2——电话       |\n");
    printf("\t|     3——年龄       |\n");
    printf("\t|     4——返回       |\n");
    printf("\t|---------------------|\n");
    printf("请选择:");
    scanf("%d",&m);
    while(m!=1&&m!=2&&m!=3&&m!=4)
    {
        printf("输入错误！");
        scanf("%d",&m);
    }
    if(m==1)
    {
        char s[20];
        int i=0;
        printf("\t请输入想查询的姓名:");
        scanf("\t%s",s);
        while(strcmp(per[i]).name,s)!=0&&i<n)
            i++;
        if(i==n)
        {
            printf("\t通讯录没有此人\n");
            return;
        }
            printf("\t此人编号:%d\n",per[i].score);
            printf("\t此人年龄:%s\n",per[i].age);
            printf("\t电话号码:%s\n",per[i].num);
            printf("\t通讯地址:%s\n",per[i].adds);
            printf("\t电子邮箱:%s\n",per[i].email);
    }
}

void Change(Person per[],int n);
{
    char s[20];
    int i=0;
    printf("\t请输入想修改的记录的名字:");
    scanf("%s",s);
    while(strcmp(per[i].name),s)!=0&&i<n)
        i++;
    if(i==n)
    {
        printf("\t通讯录中没有此人！\n");
        return;
    }
    printf("\t编号:");
    scanf("\t%d",&per[i].score);
    printf("\t姓名:");
    scanf("\t%s",per[i].name);
    printf("\t年龄:");
    scanf("\t%s",per[i].age);
    printf("\t电话号码:");
    scanf("\t%s",per[i].num);
    printf("\t通讯地址:");
    scanf("\t%s",per[i].adds);
    printf("\t电子邮箱:");
    scanf("\t%s",per[i].email);
    printf("\t修改成功！");
}

void main();
{
    int n;
    for(;;)
    {
        switch(menu_select())
        {
        case 1:
            printf("\n\t添加到通讯录\n");
            n=Input(pe,n);
            break;

        case 2:
            printf("\n\t\t\t通讯记录表\n");
            Display(pe,m);
            break;

        case 3:
            printf("\n\t从通讯录中删除记录\n");
            n=Delete_a_record(pe,n);
            break;

        case 4:
            printf("\n\t从通讯录中查找记录\n");
            Query_a_record(pe,n);
            printf("\t");
            system("pause");
            break;

        case 5:
            printf("\n\t修改通讯录中的记录\n");
            change(pe,n);
            printf("\t");
            system("pause");
            break;
            
        case 6:
            printf("\n\t按编号排序");
            sort(pe,n);
            printf("\t");
            system("pause");
            break;

        case 0:
            printf("\n\t\t谢谢使用，再见!\n");
        }
    }
}

同样是使用strcmp函数比较编号num的大小
然后用一个快排或者神魔的交换一下数据就好了

有代码吗？神魔和快排不失很懂？

#include"head.h"

void menu()
{
    printf("                主菜单                    \n");
    printf("                1.请输入学生信息        \n");
    printf("                2.学生信息显示            \n");
    printf("                3.按姓名查找            \n");
    printf("                4.删除学生信息            \n");
    printf("                5.增加学生信息            \n");
    printf("                6.修改学生信息            \n");
    printf("                7.保存到文件            \n");
    printf("                8.读取文件                \n");
    printf("                9.拷贝文件                \n");
    printf("                10.排序                    \n");
    printf("                11.退出                    \n");
}

void menu_system()
{
    menu();
    int a,lenth=0;
while (1){
    do{
        printf("请输入所选功能号：\n");
        scanf("%d", &a);
    } while (a < 1 || a>11);
    switch (a)
    {
    case 1:lenth=enter_info(stu); break;
    case 2:out_info(stu,lenth); break;
    case 3:search_name(stu,lenth); break;
    case 4:lenth=delet(stu,lenth); break;
    case 5:lenth=add(stu,lenth); break;
    case 6: modify(stu, lenth); break;
    case 7:write(stu, lenth); break;
    case 8:read(stu, lenth); break;
    case 9:copy(); break;
    case 10:sort(stu, lenth); break;
    case 11:exit(0);
    }
    menu();
    }
}

int enter_info(students stu[])
{
    int i,n;
    system("cls");
    printf("please input how many people's info that you want input！\n");
    scanf("%d",&n);
    for (i = 0; i < n; i++)
    {   system("cls");
        printf("input %dth xuehao!\n", i + 1);
        scanf_s("%s", stu[i].num, 20);
        printf("input %dth name!\n", i + 1);
        scanf_s("%s", stu[i].name, 30);
        printf("input %dth sex!\n", i + 1);
        scanf_s("%s", stu[i].sex, 4);
        printf("input %dth age!\n", i + 1);
        scanf_s("%d", &stu[i].age);
    }                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
    return n;
}

void out_info(students stu[],int n)
{
    system("cls");
    int i;
    printf("--------------students list----------------------\n");
    printf("NO.        name        sex        age\n");
    for (i = 0; i < n; i++)
    {
        printf("%s        %s        %s        %d", stu[i].num, stu[i].name, stu[i].sex, stu[i].age);
        printf("\n");
    }
    printf("------------------------------------------------\n");
}

int find_name(students stu[],int n,char* name)
{
    int i;
    for (i = 0; i < n; i++)
    {
        if (strcmp(name, stu[i].name) == 0)
            return i;
    }
    return -1;
}

int find_num(students stu[], int n,char* num)
{
    int i;
    for (i = 0; i < n; i++)
    {
        if (strcmp(num, stu[i].num) == 0)
            return i;
    }
    return -1;
}

int by_which()
{
   
    int a;
    printf("------------------------------------------------\n");
    printf("            1.by student name                    \n");
    printf("            2.by student number                    \n");
    printf("------------------------------------------------\n");
    do{
        printf("        choise:");
        scanf("%d", &a);
    } while (a < 1 || a>2);
    system("cls");
    return a;
}
void search_name(students stu[],int n)
{
    system("cls");
    int i;
    switch (by_which())
    {
    case 1:
        char name[30];
        printf("please enter name that you want search!\n");
        scanf("%s", name, 30);
        i = find_name(stu, n, name);
        if (i == -1)
        {
            printf("--------------students search list----------------------\n");
            printf("查无此人！\n");
        }
        else
        {
            printf("--------------students search list----------------------\n");
            printf("NO.        name        sex        age\n");
            printf("%s        %s        %s        %d", stu[i].num, stu[i].name, stu[i].sex, stu[i].age);
            printf("\n");
        }break;
    default:
        char num[20];
        printf("please enter num that you want search!\n");
        scanf("%s", num, 20);
        i = find_num(stu, n, num);
        if (i == -1)
        {
            printf("--------------students search list----------------------\n");
            printf("查无此人！\n");
        }
        else
        {
            printf("--------------students search list----------------------\n");
            printf("NO.        name        sex        age\n");
            printf("%s        %s        %s        %d", stu[i].num, stu[i].name, stu[i].sex, stu[i].age);
            printf("\n");
        }break;
    }
}

int delet(students stu[],int n)
{
    int i,j;
    system("cls");
    switch (by_which())
    {
    case 1:
        char name[30];
        printf("please enter name that you want delet!\n");
        scanf("%s", name, 30);
        i = find_name(stu, n, name);
        if (i == -1)
        {
            printf("--------------students search list----------------------\n");
            printf("查无此人！\n");
        }
        else
        {
            printf("deleting......!\n");
            for (j = i; j <n; j++)
            {
                strcpy_s(stu[j].num, strlen(stu[j + 1].num) + 1, stu[j + 1].num);
                strcpy_s(stu[j].name, strlen(stu[j + 1].name) + 1, stu[j + 1].name);
                strcpy_s(stu[j].sex, strlen(stu[j + 1].sex) + 1, stu[j + 1].sex);
                stu[j].age = stu[j + 1].age;
            }
            printf("delet succuse");
            n--;
        }
        return n;
        break;
    default:
        char num[20];
        printf("please enter num that you want delet!\n");
        scanf("%s", num, 20);
        i = find_num(stu, n, num);
        if (i == -1)
        {
            printf("--------------students search list----------------------\n");
            printf("查无此人！\n");
        }
        else
        {
            printf("deleting......!\n");
            for (j = i; j <n; j++)
            {
                strcpy_s(stu[j].num, strlen(stu[j + 1].num) + 1, stu[j + 1].num);
                strcpy_s(stu[j].name, strlen(stu[j + 1].name) + 1, stu[j + 1].name);
                strcpy_s(stu[j].sex, strlen(stu[j + 1].sex) + 1, stu[j + 1].sex);
                stu[j].age = stu[j + 1].age;
            }
            printf("delet succuse");
            n--;
        }
        return n;
        break;
    }
}

int add(students stu[],int n)
{
    int i, j;
    system("cls");
    switch (by_which())
    {
    case 1:
        char name[30];
        printf("please enter name that you want add!\n");
        scanf("%s", name, 30);
        i = find_name(stu, n, name);
        if (i == -1)
        {
            printf("--------------students search list----------------------\n");
            printf("查无此人！\n");
        }
        else
        {
            printf("adding......!\n");
            for (j = n; j >i; j--)
            {
                strcpy_s(stu[j].num, strlen(stu[j - 1].num) + 1, stu[j - 1].num);
                strcpy_s(stu[j].name, strlen(stu[j - 1].name) + 1, stu[j - 1].name);
                strcpy_s(stu[j].sex, strlen(stu[j - 1].sex) + 1, stu[j - 1].sex);
                stu[j].age = stu[j - 1].age;
            }
            printf("input %dth xuehao!\n", i + 1);
            scanf_s("%s", stu[i].num, 20);
            printf("input %dth name!\n", i + 1);
            scanf_s("%s", stu[i].name, 30);
            printf("input %dth sex!\n", i + 1);
            scanf_s("%s", stu[i].sex, 4);
            printf("input %dth age!\n", i + 1);
            scanf_s("%d", &stu[i].age);
            n++;
            printf("add succuse");
        }
        return n;
        break;
    default:
        char num[20];
        printf("please enter num that you want add!\n");
        scanf("%s", num, 20);
        i = find_num(stu, n, num);
        if (i == -1)
        {
            printf("--------------students search list----------------------\n");
            printf("查无此人！\n");
        }
        else
        {
            printf("adding......!\n");
            for (j = n; j >i; j--)
            {
                strcpy_s(stu[j].num, strlen(stu[j - 1].num) + 1, stu[j - 1].num);
                strcpy_s(stu[j].name, strlen(stu[j - 1].name) + 1, stu[j - 1].name);
                strcpy_s(stu[j].sex, strlen(stu[j - 1].sex) + 1, stu[j - 1].sex);
                stu[j].age = stu[j - 1].age;
            }
            printf("input %dth xuehao!\n", i + 1);
            scanf_s("%s", stu[i].num, 20);
            printf("input %dth name!\n", i + 1);
            scanf_s("%s", stu[i].name, 30);
            printf("input %dth sex!\n", i + 1);
            scanf_s("%s", stu[i].sex, 4);
            printf("input %dth age!\n", i + 1);
            scanf_s("%d", &stu[i].age);
            n++;
            printf("add succuse");
        }
        return n;
        break;
    }
}

void modify(students stu[], int n)
{
    int i;
    switch (by_which()){
    case 1:
        char name[30];
        printf("please enter name that you want search!\n");
        scanf("%s", name, 30);
        i = find_name(stu, n, name);
        if (i == -1)
        {
            printf("--------------students search list----------------------\n");
            printf("查无此人！\n");
        }
        else
        {
            int a;
            printf("------------------------------------------------\n");
            printf("            1.modify name                        \n");
            printf("            2.modify number                        \n");
            printf("            3.modify sex                        \n");
            printf("            4.modify age                        \n");
            printf("------------------------------------------------\n");
            do{
                printf("        choise:");
                scanf("%d", &a);
            } while (a < 1 || a>4);
            system("cls");
            switch (a)
            {
            case 1:
                char name[30];
                printf("please input the name you want modify!\n");
                scanf("%s", name, 30);
                strcpy_s(stu[i].name, strlen(name) + 1, name);
                printf("modify success!\n");
                break;
            case 2:
                char num[30];
                printf("please input the num you want modify!\n");
                scanf("%s", num, 30);
                strcpy_s(stu[i].num, strlen(num) + 1, num);
                printf("modify success!\n");
                break;
            case 3:
                char sex[4];
                printf("please input the sex you want modify!\n");
                scanf("%s", sex, 4);
                strcpy_s(stu[i].sex, strlen(sex) + 1, sex);
                printf("modify success!\n");
                break;
            default:
                int age;
                printf("please input the age you want modify!\n");
                scanf("%d", &age);
                stu[i].age = age;
                printf("modify success!\n");
                break;
            }
        }break;
    default:
        char num[20];
        printf("please enter num that you want search!\n");
        scanf("%s", num, 20);
        i = find_num(stu, n, num);
        if (i == -1)
        {
            printf("--------------students search list----------------------\n");
            printf("查无此人！\n");
        }
        else
        {
            int a;
            printf("------------------------------------------------\n");
            printf("            1.modify name                        \n");
            printf("            2.modify number                        \n");
            printf("            3.modify sex                        \n");
            printf("            4.modify age                        \n");
            printf("------------------------------------------------\n");
            do{
                printf("        choise:");
                scanf("%d", &a);
            } while (a < 1 || a>4);
            system("cls");

            switch (a)
            {
            case 1:
                char name[30];
                printf("please input the name you want modify!\n");
                scanf("%s", name, 30);
                strcpy_s(stu[i].name, strlen(name) + 1, name);
                printf("modify success!\n");
                break;
            case 2:
                char num[30];
                printf("please input the num you want modify!\n");
                scanf("%s", num, 30);
                strcpy_s(stu[i].num, strlen(num) + 1, num);
                printf("modify success!\n");
                break;
            case 3:
                char sex[4];
                printf("please input the sex you want modify!\n");
                scanf("%s", sex, 4);
                strcpy_s(stu[i].sex, strlen(sex) + 1, sex);
                printf("modify success!\n");
                break;
            default:
                int age;
                printf("please input the age you want modify!\n");
                scanf("%d", &age);
                stu[i].age = age;
                printf("modify success!\n");
                break;
            }
        }
    }
}

void write(students stu[],int n)
{
    system("cls");
    int i;
    FILE *file;
    if ((file = fopen("F:system.txt", "w")) == NULL)
    {
        printf("write error!");
    }
    else
    {
        printf("write success!");
        fprintf(file, "--------------students list----------------------\n");
        fprintf(file, "NO.        name        sex        age\n");
        for (i = 0; i < n; i++)
        {
            fprintf(file, "%s        %s        %s        %d", stu[i].num, stu[i].name, stu[i].sex, stu[i].age);
            fprintf(file, "\n");
        }
        fprintf(file, "------------------------------------------------\n");
        fclose(file);
    }
}

void read(students stu[], int n)
{
    system("cls");
    char buf[500] ={NULL};
    FILE *file;
    if ((file = fopen("F:system.txt", "r")) == NULL)
    {
        printf("read error!\n");
    }
    else
    {
        printf("read success!\n");
        while (!feof(file))
        {
            printf("%s", buf);
            fgets(buf, 500, file);
        }
        fclose(file);
    }
}

void copy()
{
    char outfile[20];
    char buf[100] = {NULL};
    FILE*sfp,*fp;
    sfp = (fopen("F:system.txt", "r"));
    if (sfp ==NULL)
    {
        printf("read error!\n");
    }
    else
    {
        printf("read success!\n");
        printf("请输入要拷贝到的文件：形式如D:\\text\\t.txt:\n");
        scanf("%s",outfile,20);
        fp = (fopen(outfile, "w"));
        if (fp == NULL)
        {
            printf("write error!\n");
        }
        else
        {
            while (!feof(sfp))
            {
                fputs(buf, fp);
                fgets(buf, 100, sfp);
            }
            fclose(sfp);
            fclose(fp);
        }
    }
}
void sort(students stu[], int n)
{
    struct students
    {
        char num[20];
        char name[30];
        char sex[4];
        int age;
    }t[N];
    int i, j,min;
    switch (by_which())
    {
    case 1:
        for (i = 0; i < n; i++)
        {
            min = i;
            for (j = i + 1; j < n; j++)
            {
                if (strcmp(stu[min].name, stu[j].name) > 0)
                {
                    min = j;
                }
            }
            strcpy_s(t[1].num, strlen(stu[i].num) + 1, stu[i].num);
            strcpy_s(stu[i].num, strlen(stu[min].num) + 1, stu[min].num);
            strcpy_s(stu[min].num, strlen(t[1].num) + 1, t[1].num);   
            
            strcpy_s(t[1].name, strlen(stu[i].name) + 1, stu[i].name);
            strcpy_s(stu[i].name, strlen(stu[min].name) + 1, stu[min].name);
            strcpy_s(stu[min].name, strlen(t[1].name) + 1, t[1].name);
            
            strcpy_s(t[1].sex, strlen(stu[i].sex) + 1, stu[i].sex);
            strcpy_s(stu[i].sex, strlen(stu[min].sex) + 1, stu[min].sex);
            strcpy_s(stu[min].sex, strlen(t[1].sex) + 1, t[1].sex);
        }
        break;
    default:
        for (i = 0; i < n; i++)
        {
            min = i;
            for (j = i + 1; j < n; j++)
            {
                if (strcmp(stu[min].num, stu[j].num) > 0)
                {
                    min = j;
                }
            }
            strcpy_s(t[1].num, strlen(stu[i].num) + 1, stu[i].num);
            strcpy_s(stu[i].num, strlen(stu[min].num) + 1, stu[min].num);
            strcpy_s(stu[min].num, strlen(t[1].num) + 1, t[1].num);

            strcpy_s(t[1].name, strlen(stu[i].name) + 1, stu[i].name);
            strcpy_s(stu[i].name, strlen(stu[min].name) + 1, stu[min].name);
            strcpy_s(stu[min].name, strlen(t[1].name) + 1, t[1].name);

            strcpy_s(t[1].sex, strlen(stu[i].sex) + 1, stu[i].sex);
            strcpy_s(stu[i].sex, strlen(stu[min].sex) + 1, stu[min].sex);
            strcpy_s(stu[min].sex, strlen(t[1].sex) + 1, t[1].sex);
        }
        break;
    }
}
void main(){
    menu_system();
    system("pause");
}