60分求助

#include<bits/stdc++.h>
using namespace std;
int x,y,n;
char op,a[1000],b[1000];
int deal()
{
    switch(op)
    {
        case'+':return x+y;
        case'-':return x-y;
        case'*':return x*y;
    }
}
int main()
{
    scanf("%d\n",&n);
    while(n--)
    {
        fgets(a,sizeof(a),stdin);
        switch(a[0])
        {
            case'a':op='+';sscanf(a+2,"%d%d",&x,&y);break;
            case'b':op='-';sscanf(a+2,"%d%d",&x,&y);break;
            case'c':op='*';sscanf(a+2,"%d%d",&x,&y);break;
            default:sscanf(a+2,"%d%d",&x,&y);break;
        }
        sprintf(b,"%d%c%d=%d",x,op,y,deal());
        puts(b);
        printf("%d\n",strlen(b));
    }
    return 0;
}