求助帖 为什么测试对 交就不对

#include <iostream>
#include <string>
using namespace std;
int b[20];
void number (string x){
    while(x[0]>'9' || x[0]<'0') x=x.substr(1,x.size());
    b[0]=0;
    int i=0;
    while(x[i]!=' '){
        b[0]= b[0]*10 + (x[i]-'0');
        i++;
    }
    while(x[i]==' ')i++; 
    b[1]=0;
    while(i<x.size()){
        b[1]= b[1]*10 + (x[i]-'0');
        i++;
    }
}

int length(int x){
    if(x==0) return 1;
    else{
        int len=0;
        if(x<0) len++;
        x=abs(x);
        while(x){
            x=x/10;
            len++;
        }
        return len;
    }
}
int main(){
    //freopen("1.txt","r", stdin);
    int n;
    cin>>n;
    string a[100];
    getline(cin,a[0]);
    for (int i=0;i<n;i++){
        getline (cin,a[i]);
        if (a[i][0]>='0' &&a[i][0]<='9')
            a[i]=a[i-1].substr(0,2) + a[i];
        if (a[i][0]=='a') {
            number (a[i]);
            cout<<b[0]<<'+'<<b[1]<<'='<<b[0]+b[1]<<endl;
            cout<<length(b[0])+length(b[1])+length(b[0]+b[1])+2<<endl;
        }
        if (a[i][0]=='b') {
            number (a[i]);
            cout<<b[0]<<'-'<<b[1]<<'='<<b[0]-b[1]<<endl;
            cout<<length(b[0])+length(b[1])+length(b[0]+b[1])+2<<endl;
        }
        if (a[i][0]=='c') {
            number (a[i]);
            cout<<b[0]<<'*'<<b[1]<<'='<<b[0]*b[1]<<endl;
            cout<<length(b[0])+length(b[1])+length(b[0]+b[1])+2<<endl;
        }

    }
    return 0;
}