1、填空（小学生加减法项目练习）
#include "stdio.h"
#include "time.h"
#include "stdlib.h"
void main()
{
    int option,a,b,sum,cha;
    int i,right=0;
    char ch;
    do{
        printf("========欢迎进行10以内加减法练习========\n");
        printf("========================================\n");
        printf("              1、加法练习\n");
        printf("              2、减法练习\n");
        printf("              3、退出\n");
        printf("========================================\n");
        printf("请输入1或2或3，并按回车键进入：");
        scanf("%d",&option);
        system("cls"); //包含在stdlib头文件中
        switch (option){
            case 1://加法练习
                srand(time(0));
                循环5次出加法题目;(这里加代码)
                printf("你算对了%d道题，算错了%d道题。\n",right,5-right);
                break;
            case 2://减法练习
                需要加代码
            case 3:
                printf("退出");
                           （加代码）
                break;
            default:
                printf("输入错误\n");
                ch='s';

        }
        if (ch=='n')
            break;
        if (ch=='s'){
            ch='y';
            continue;
        }
        printf("是否继续Y/N");
        fflush(stdin);//清除缓冲区中的数据,包含在stdio.h头文件中
        scanf("%c",&ch);
        system("cls"); //包含在stdlib头文件中        
    }while(ch=='Y'||ch=='y');
    system("cls");
    printf("再见！\n");

用一个for循环控制次数，用 srand(time(0))产生两个随机数a，b，如果用户输入a+b的值，则right++。
减法同理

可以帮我码一遍吗

你试试这个···
#include "stdio.h"
#include "time.h"
#include "stdlib.h"
void main()
{
    int option,a,b,minus,sum,temp,i,right=0;
    char ch;
    do{
        printf("========欢迎进行10以内加减法练习========\n");
        printf("========================================\n");
        printf("              1、加法练习\n");
        printf("              2、减法练习\n");
        printf("              3、退出\n");
        printf("========================================\n");
        printf("请输入1或2或3，并按回车键进入：");
        scanf("%d",&option);
        system("cls"); //包含在stdlib头文件中
        switch (option)
        {
            case 1:     //加法练习
                srand(time(0));                    
                for(i=0;i<5;i++)
                {
                  a=rand()%(10);
                  b=rand()%(10);
                  printf("%d + %d =?\n",a,b);
                  scanf("%d",&sum);
                      if(sum==a+b)
                          right++;
                }   
                printf("你算对了%d道题，算错了%d道题。\n",right,5-right);
                break;
            case 2:      //减法练习
                srand(time(0));                    
                for(i=0;i<5;i++)
                {
                  a=rand()%(10);
                  b=rand()%(10);
                  if(a<b) //考虑到小学生应该不会负数
                  {
                    temp=a;
                    a=b;
                    b=temp;
                  }
                  printf("%d - %d =?\n",a,b);
                  scanf("%d",&minus);
                      if(minus==a-b)
                          right++;
                }
                printf("你算对了%d道题，算错了%d道题。\n",right,5-right);
                break;
            case 3:         
                break;
            default:
                printf("输入错误\n");
                ch='s';

        }
        if (ch=='n')
            break;
        if (ch=='s')
        {
            ch='y';
            continue;
        }
        printf("是否继续Y/N");
        fflush(stdin);//清除缓冲区中的数据,包含在stdio.h头文件中
        scanf("%c",&ch);
        system("cls"); //包含在stdlib头文件中        
    }while(ch=='Y'||ch=='y');
    system("cls");
    printf("再见！\n");
}

  这样。。。

结果没清除，第二遍做的话第一次的结果会累加起来


[ 本帖最后由 jcslt 于 2009-11-18 17:42 编辑 ]