#include<stdio.h>
#include<stdlib.h> //rand()
#include <time.h> //

int main()
{
   
    time_t t;
 
    int randint,flag=1;
    float x;
    double result,p;
    int optr,a,b,c=0,i=1;
    char array[4]={'+','-','*','/'};

    srand( time(&t));
    printf("10以内的四则运算，提示:若答案有小数，请保留小数点后两位");

    while(flag==1)
    {
        randint = rand();
           a=randint%10;
        randint = rand();
         b=randint%10;

        randint = rand();
        randint=randint%4;
        optr=array[randint];

        printf("\n第%d题 : %d %c %d = ", i,a,optr,b);
        scanf("%f",&x);

        switch(optr)        
        {
         case '+':
            result=a+b;
            break;

        case '-':
            result=a-b;
            break;

        case '*':
            result=a*b;
            break;

        case '/':
            if(b==0)
            {
                while(b!=0)
                 b=randint%10;
            }
            result=(double)a/b;
            break;

        }

        if(result==x)
        {
            printf("正确!");
            c++;
            printf("\n若继续请输入1，结束请输入0:");
            scanf("%d",&flag);

            while(flag!=0&&flag!=1)
            {               
                printf("\n你的输入有误，请重新输入:");
                scanf("%d",&flag);
            }
        }
        else
        {
            printf("结果错误，答案为: %.2f ",result);
            printf("\n若继续请输入1，结束请输入0:");
            scanf("%d",&flag);
            while(flag!=0&&flag!=1)
            {               
                printf("你的输入有误，请重新输入:");
                scanf("%d",&flag);
            }
        }
        i++;
    }
    //统计结果
    p=((float)c/(i-1))*100;       //正确率
    printf("\n\n总共%d道题，答对%d题，正确率为%%%.2f\n",i-1,c,p);
    return 0;
}

计算加减乘除

#include <stdio.h>
#include <stdlib.h> //rand()
#include <time.h> //
#include <math.h>

int main()
{
    
    time_t t;

    int randint,flag=1; 
    float x;
    float result,p;
    int optr,a,b,c=0,i=1;
    char array[4]={'+','-','*','/'};

    srand( time(&t));
    printf("10以内的四则运算，提示:若答案有小数，请保留小数点后两位");

    while(flag==1)
    {
        randint = rand();//先确定运算符，再去确定运算数字
        randint=randint%4;
        optr=array[randint];
        
        randint = rand();
        a=randint%10;
        do
        {
            randint = rand();
            b = randint % 10;
        }while(optr == '/' && b == 0);//这样就可以避开除数为0的情况
        

        printf("\n第%d题 : %d %c %d = ", i,a,optr,b);
        scanf("%f",&x);

        switch(optr)        
        {
         case '+':
            result=a+b;
            break;

        case '-':
            result=a-b;
            break;

        case '*':
            result=a*b;
            break;

        case '/':
               result = (float) a/b;
            break;
            
        }

        if(fabs(result-x)<0.005 || result == x)//浮点数运算简单用'=='判等是不对的
        {
            printf("正确!");
            c++;
            printf("\n若继续请输入1，结束请输入0:");
            scanf("%d",&flag);

            while(flag!=0&&flag!=1)
            {                
                printf("\n你的输入有误，请重新输入:");
                scanf("%d",&flag);
            }
        }
        else
        {
            printf("结果错误，答案为: %.2f ",result);
            printf("\n若继续请输入1，结束请输入0:");
            scanf("%d",&flag);
            while(flag!=0&&flag!=1)
            {                
                printf("你的输入有误，请重新输入:");
                scanf("%d",&flag);
            }
        }
        i++;
    }
    //统计结果
    p=((float)c/(i-1))*100;       //正确率
    printf("\n\n总共%d道题，答对%d题，正确率为%%%.2f\n",i-1,c,p);
    return 0;
}

[ 本帖最后由 我爱吃青菜 于 2015-6-7 11:12 编辑 ]

谢谢大神