现在你要为一个小学开发一个四则运算练习的系统。用户可以选择四则运算的范围，比如10以内的四则运算等等，用户还可以输入需要做多少题，然后，程序输出题目，每输出一题，用户就要输入一个答案，最后系统给出一个成绩，比如一共出20题，用户答对了12题，那么输出"共20题，答对12题，正确率为0.6"。

我刚学c语言 ，所以各位大大们做的不要太难！
麻烦各位大大了！

也是以前老师叫偶们做的题，不够偶是自己写的

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include <math.h>
void math()
{
    double dim = 0;
    int num = 0;
    int i = 0;
    int right = 0 ;//
    int wrong = 0 ;//
    time_t t;
    int choose = 0;
    int op_1 = 0 ,op_2 = 0;
    double result = 0;
    double trueresult = 0;
    srand((unsigned)time(&t));
    printf("Enter the dimension:");
    scanf("%lf" ,&dim);
    //printf("%f\n",dim);
    printf("Enter how many question you want to do:");
    scanf("%d" ,&num);
    //printf("%d\n",num);
    for(i = 0 ; i < num ; i++)
    {
        choose = rand()%4;
        switch(choose)
        {
        case 0://add
            op_1 = rand()%(num+1);
            op_2 = rand()%(num+1);
            printf("%d + %d = " , op_1 , op_2);
            scanf("%lf" , &result);
            trueresult = (double)op_1 + op_2;
            if( fabs(result-trueresult) < 0.01 )
            {
                right++;
                printf("Congratulations ,you give the right answer!\n");
            }
            else
            {
                wrong++;
                printf("Oh, it's so pity,your answer is wrong,but donot lose heart!\n");
            }
            break;
        case 1://substract
            op_1 = rand()%num;
            op_2 = rand()%num;
            if(op_1 > op_2)
            {
                printf("%d - %d = " , op_1 , op_2);
                scanf("%lf" , &result);
                trueresult =(double) op_1 - op_2;
                if( fabs(result-trueresult) < 0.01 )
                {
                    right++;
                    printf("Congratulations ,you give the right answer!\n");
                }
                else
                {
                     wrong++;
                    printf("Oh, it's so pity,your answer is wrong,but donot lose heart!\n");
                }
            }
            else
            {
                printf("%d - %d = " , op_2 , op_1);
                scanf("%lf" , &result);
                trueresult =(double)  op_2 - op_1;
                if( fabs(result-trueresult) < 0.01 )
                {
                    right++;
                    printf("Congratulations ,you give the right answer!\n");
                }
                else
                {
                     wrong++;
                    printf("Oh, it's so pity,your answer is wrong,but donot lose heart!\n");
                }
            }
            break;
        case 2://mutiply
            op_1 = rand()%num;
            op_2 = rand()%num;
            printf("%d * %d = " , op_1 , op_2);
            scanf("%lf" , &result);
            trueresult = (double) op_1 * op_2;
            if( fabs(result-trueresult) < 0.01 )
            {
                right++;
                printf("Congratulations ,you give the right answer!\n");
            }
            else
            {
                   wrong++;
                printf("Oh, it's so pity,your answer is wrong,but donot lose heart!\n");
            }
            break;
        case 3:
            op_1 = rand()%num;
            op_2 = rand()%num;
            while(op_2 == 0)
               op_2 = rand()%num;
            printf("%d / %d = " , op_1 , op_2);
            scanf("%lf" , &result);
            trueresult = (double)op_1 / op_2;
            if( fabs(result-trueresult) < 0.01 )
            {
                right++;
                printf("Congratulations ,you give the right answer!\n");
            }
            else
            {
                wrong++;
                printf("Oh, it's so pity,your answer is wrong,but donot lose heart!\n");
            }
            break;
        }
    }
    printf("Total question is:%d\n" , num);
    printf("Given right answer is:%d\n" , right);
    printf("Given worng answer is:%d\n" , wrong);
    printf("Correct answer rate is:%f\n" , (double)right/num);
}
int main()
{
    math();
    return 0;
}
仅供参考！！！呵呵

可是，为什么写“C++问题”呢？

标题党