应用回溯法，谢谢大家。
找出n个自然数（1，2，3，。。。。，N）中r个数的组合。例如：n=5,r=3,所有组合为：
A[1] A[2] A[3]

5 4 3
5 4 2
5 4 1
5 3 2
5 3 1
5 2 1
4 3 2
4 3 1
4 2 1
3 2 1

排数时从A[1]->A[2]->A[3]，后一个至少比前一个数小1，并且应该满足r_i+A[r_i]>r这个关系。若r_i+A[r_i]<=r就要回溯，该关系就是回溯的条件。为直观起见，当输出一组组合数后，若最后一位为1，也应该做一次回溯（若不回溯，便由上述回溯条件处理）。

c程序高手们,你们好.我现在做c课程设计,我不会做流程图,请你们帮帮我!!!

这是我的程序


#include "stdio.h" /*I/O函数*/
#include "stdlib.h" /*其它说明*/
#include "string.h" /*字符串函数*/
#include "conio.h" /*屏幕操作函数*/
#include "mem.h" /*内存操作函数*/
#include "ctype.h" /*字符操作函数*/
#include "alloc.h" /*动态地址分配函数*/
struct score
{
int mingci;
char xuehao[8];
char mingzi[20];
float score[6];
}data,info[1000];
int i,j,k=0;
char temp[20],ch;
FILE *fp,*fp1;

void shuru()
{
if((fp=fopen("s_score.txt","ab+"))==NULL)
{
printf("cannot open this file.\n");
getch();exit(0);
}
for(i=0;i<=1000;i++)
{
printf("\nPlease shuru xuehao:");
gets(data.xuehao);
printf("Please shuru mingzi:");
gets(data.mingzi);
printf("Please shuru yuwen score:");
gets(temp);data.score[0]=atof(temp);
printf("Please shuru shuxue score:");
gets(temp);data.score[1]=atof(temp);
printf("Please input yingyu score:");
gets(temp);data.score[2]=atof(temp);
printf("Please shuru wuli score:");
gets(temp);data.score[3]=atof(temp);
printf("Please shur huaxue score:");
gets(temp);data.score[4]=atof(temp);
data.score[5]=data.score[0]+data.score[1]+data.score[2]+data.score[3]+data.score[4];
fwrite(&data,sizeof(data),1,fp);
printf("another?y/n");
ch=getch();
if(ch=='n'||ch=='N')
break;
} fclose(fp);
}
void xianshi()
{
float s;int n;
if((fp=fopen("s_score.txt","rb+"))==NULL)
{
printf("Cannot reading this file.\n");
exit(0);
}
for(i=0;i<=1000;i++)
{
if((fread(&info[i],sizeof(info[i]),1,fp))!=1)
break;
}
printf("\nxuehao mingzi yuwen shuxue yingyu wuli huauxue zhongfen\n");
for(j=0,k=1;j<i;j++,k++)
{
info[j].mingci=k;
printf("%6s %8s %3.1f %3.1f %3.1f %3.1f %3.1f %3.1f\n",info[j].xuehao,info[j].mingzi,info[j].score[0],info[j].score[1],info[j].score[2],info[j].score[3],info[j].score[4],
info[j].score[5]);
}
getch();
fclose(fp);
}

void xiugai()
{
if((fp=fopen("s_score.txt","rb+"))==NULL||(fp1=fopen("temp.txt","wb+"))==NULL)
{
printf("Cannot open this file.\n");
exit(0);
}
printf("\nPLease shuru xiugai xuehao:");
scanf("%d",&i); getchar();
while((fread(&data,sizeof(data),1,fp))==1)
{
j=atoi(data.xuehao);
if(j==i)
{
printf("xuehao:%s\nmingzi:%s\n",data.xuehao,data.mingzi);
printf("Please shuru mingzi:");
gets(data.mingzi);
printf("Please shuru yuwen score:");
gets(temp);data.score[0]=atof(temp);
printf("Please shuru shuxue score:");
gets(temp);data.score[1]=atof(temp);
printf("Please input yingyu score:");
gets(temp);data.score[2]=atof(temp);
printf("Please input wuli score:");
gets(temp);data.score[3]=atof(temp);
printf("Please input huaxue score:");
gets(temp);data.score[4]=atof(temp);
data.score[5]=data.score[0]+data.score[1]+data.score[2]+data.score[3]+data.score[4];

} fwrite(&data,sizeof(data),1,fp1);
}
fseek(fp,0L,0);
fseek(fp1,0L,0);
while((fread(&data,sizeof(data),1,fp1))==1)
{
fwrite(&data,sizeof(data),1,fp);
}

fclose(fp);
fclose(fp1);
}
void chazhao()
{
if((fp=fopen("s_score.txt","rb"))==NULL)
{
printf("\nCannot open this file.\n");
exit(0);
}
printf("\nPLease shuru xuehao chakan:");
scanf("%d",&i);
while(fread(&data,sizeof(data),1,fp)==1)
{
j=atoi(data.xuehao);
if(i==j)
{
printf("xuehao:%s mingzi:%s\nyuwen:%f\n shuxue:%f\n yingyu:%f\n wuli:%f\n huaxue:%f\n ",data.xuehao,data.mingzi,data.score[0],data.score[1],data.score[2],data.score[3],data.score[4],data.score[5]);
}getch();
}
}
void shanchu()
{
if((fp=fopen("s_score.txt","rb+"))==NULL||(fp1=fopen("temp.txt","wb+"))==NULL)
{
printf("\nopen score.txt was failed!");
getch();
exit(0);
}
printf("\nPlease input ID which you want to del:");
scanf("%d",&i);getchar();
while((fread(&data,sizeof(data),1,fp))==1)
{
j=atoi(data.xuehao);
if(j==i)
{

printf("Anykey will delet it.\n");
getch();
continue;
}
fwrite(&data,sizeof(data),1,fp1);
}
fclose(fp);
fclose(fp1);
remove("s_score.txt");
rename("temp.txt","s_score.txt");
printf("Data delet was succesful!\n");
printf("Anykey will return to main.");
getch();
}
main()
{
while(1)
{
clrscr(); /*清屏幕*/
gotoxy(1,1); /*移动光标*/
textcolor(YELLOW); /*设置文本显示颜色为黄色*/
textbackground(BLUE); /*设置背景颜色为蓝色*/
window(1,1,99,99); /* 制作显示菜单的窗口，大小根据菜单条数设计*/
clrscr();
printf("*************welcome to use student manage******************\n");
printf("*************************menu********************************\n");
printf("* ========================================================= * \n");
printf("* 1>shuru 2>xiugai * \n");
printf("* 3>shanchu 4>chazhao * \n");
printf("* 5>xianshi 6>exit * \n");
printf("* * \n");
printf("* --------------------------------------------------------- * \n");
printf(" Please input which you want(1-6):");
ch=getch();
switch(ch)
{
case '1':shuru();break;
case '2':xiugai(); break;
case '3':shanchu(); break;
case '4':chazhao(); break;
case '5':xianshi(); break;
case '6':exit(0);
default: continue;
}
}
}