作业2 结对 四则运算

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int a[100],b[100];
char c[100],sym[5]={‘+‘,‘-‘,‘*‘,‘/‘,‘!‘};
int answer(int i);
void printanswer(int n);
void main()
{
    int n,o,count;
    time_t start,end; 
    int i;
    char r;
       srand((unsigned)time(NULL));
        while(1)
        {
            count=0;
            printf("输入需要的题目数(0退出)：");
            scanf("%d",&n);
            if(n==0) exit(0);
            start =time(NULL);
            for(i=0;i<n;i++)
            {
            a[i]=rand()%201-100;
            b[i]=rand()%201-100;
            c[i]=sym[rand()%5];
            if(c[i]==sym[4]) {
                while(a[i]<=0){
                    a[i]=rand()%201-100;
                }
                printf("%d!=",a[i]);
            }
            else if(a[i]<0&&b[i]<0) printf("(%d)%c(%d)=",a[i],c[i],b[i]);
            else if(a[i]<0&&b[i]>0) printf("(%d)%c%d=",a[i],c[i],b[i]);
            else if(a[i]>0&&b[i]<0) printf("%d%c(%d)=",a[i],c[i],b[i]);
            else printf("%d%c%d=",a[i],c[i],b[i]);
            
            scanf("%d",&o);
            if(o==answer(i)) {
                printf("正确!\n");
                count++;
            }
            else printf("错误!答案是%d\n",answer(i));
            }
            end =time(NULL);
            printf("答对了%d题,答错了%d题,",count,n-count);
            printf("用时为%d秒\n",end-start);  
        }
}
int answer(int i)
{
    int o;
        if(c[i]==sym[0]) o=a[i]+b[i];
        if(c[i]==sym[1]) o=a[i]-b[i];
        if(c[i]==sym[2]) o=a[i]*b[i];
        if(c[i]==sym[3]) o=a[i]/b[i];
        if(c[i]==sym[4]){
            o=a[i];
            for(i=a[i];i>0;i--)
                o=o*(o-1);
        }
        return o;
}