C++试题 救救孩子吧

#include<stdio.h>

int a , b , c;

int main()
{
    for(int i = 1;i <= 6;i ++)
    {
        scanf("%d",&a);
        
        b += 300;
        
        if(b < a) return !printf("超出预算\n");
        
        b -= a;
        
        c += b / 100;
        
        b -= b / 100 * 100;
    }
    
    printf("%d\n",b + c * 100 + c * 20);
}