PAT甲级 —— 1001 A+B Format (20分)

题目链接：A+B Format (20分)

题目描述

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 Specification:

Each input file contains one test case. Each case contains a pair of integers a and b where $-10{}^6\le a,b\le 10^6$. The numbers are separated by a space.

Output Specification:

For each test case, you should 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

满分代码

#include<iostream> #include<string> #include<algorithm> using namespace std; int main() { int a,b,sum; string s; cin>>a>>b; sum = a+b; s = to_string(sum); int len = s.length(); for(int i=0;i<len;i++) { cout<<s[i]; if (s[i] == '-') continue; if ((i + 1) % 3 == len % 3 && i != len - 1) cout << ","; } return 0; }

说明：这个题主要就是加逗号的位置，从右向左每3各数要加一个逗号，用模运算处理，比较简单