Analysis of Pat computer problems in Zhejiang University 1001. A + B format (20)

1001. A + B format (20) Time Limit 400 MS
The memory limit is 32000 kb.
Code length limit: 16000 B
Criterion author Chen, Yue

Calculate a + B and output the sum in standard format -- that is, the digits must be separated into groups of three by commas (unless there are less than four digits ).

Input

Each input file contains one test case. Each case contains a pair of integers A and B where-1000000 <= A, B <= 1000000. The numbers are separated by a space.

Output

For each test case, You shocould output the sum of A and B in one line. The sum must be written in the standard format.

Sample Input

-1000000 9

Sample output

-999,991

#include<iostream>#include <string>#include <algorithm>using namespace std;int main(){  int M,N,sum=0;  string  str;  int flag=0;  string::iterator it;  cin>>M>>N;  sum = M+N;  if (sum<0)  {    sum  = 0-sum;    flag=1;  }  while(sum)  {    char  ch = '0'+sum%10;    str.push_back(ch);    sum/=10;  }  if (str.empty())  cout<<"0"<<endl;  if (flag)  cout<<"-";  reverse(str.begin(),str.end());  if (!str.empty()&&str.size()<=3)  {    cout<<str;  }  else  {   int num = str.size()%3;   if (num==1)   {     cout<<*str.begin()<<",";   }   else  if (num==2)  {    cout<<*str.begin()<<*(str.begin()+1)<<",";  }   int k=1;   for (it=str.begin()+num;it!=str.end();it++)   {     if (k==4)     {       cout<<",";       k=1;     }     cout<<*it;     k++;   }  }  cout<<endl;//  system("pause");  return 0;}