string乘法

#include <iostream>

#include<string>

#include<algorithm>

using namespace std;

string multiply(string a,string b){

string c;

int i=0,j=0;int carry=0,temp=0;

for(i=0;i<a.length();i++){

        carry=0;

for(j=0;j<b.length();j++){

cout<<(a[a.length()-1-i]-48)<<'x'<<(b[b.length()-1-j]-48)<<' ';

temp=(a[a.length()-1-i]-48)*(b[b.length()-1-j]-48)+carry;

if(temp>9){carry=temp/10;temp=temp%10;}

else{carry=0;}

if(i+j==c.length()){c.push_back(temp+48);}

else{c[i+j]+=temp;

if(c[i+j]>57){c[i+j]-=10;carry+=1;}

}

 cout<<c<<endl;

}

if(carry){

   if(i+j==c.length()){c.push_back(carry+48);}

   }

   cout<<c<<endl;

}

reverse(c.begin(),c.end());

return c;

}

int main()

{

 string a,b;cin>>a>>b;

   cout << multiply(b,a);

   return 0;

}