四则运算

include <stdio.h>

include <stdlib.h>

include <time.h>

include <math.h>

int main()
{
int i=0;
int n=0;
int x=0;
int type;
char flag;
int left, right;
float result;

printf("请输入要出的题目数量\n");
scanf("%d",&n);

srand(unsigned(time(NULL)));

while(x<n)
{
    type = rand() % 4;
    left = rand() % 100;
    right = rand() % 100;
    switch(type)
    {
    case 0:
        printf("%d + %d = ?\n", left, right);
        break;
    case 1:
        printf("%d - %d = ?\n", left, right);
        break;
    case 2:
        printf("%d * %d = ?\n", left, right);
        break;
    case 3:
        printf("%d / %d = ?\n", left, right);
        break;
    }

    i++;
    while(i>=n)
    {
        printf("一共 %d 题\n",i);
        printf("继续?[Y/N]\n");
        fflush(stdin);
        scanf("%c",&flag);
        if(flag=='Y'||flag=='y')
        {
            printf("请输入要出的题目数量\n");
            scanf("%d",&n);
            i=0;
            break;
         }
        printf("谢谢使用！\n");
        fflush(stdin);
        getchar();
        return 0;
    }
}

}