1.进行分数通分;
2.比较分子;
#include <iostream>
using namespace std;
int main(void){
int a,b,c,d;
printf("请输入两个分数:\n");
scanf("%d/%d%d/%d",&a,&b,&c,&d);
if(a*d>c*b){printf("%d/%d>%d/%d",a,b,c,d);}
if(a*d<c*b){printf("%d/%d<%d/%d",a,b,c,d);}
if(a*d==c*b){printf("%d/%d=%d/%d",a,b,c,d);}
return 0;
}