PTA-Advance-1001

PROBLEM

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 $−10^6≤a,b≤10^6$. 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

ACCEPTED CODE

#include <iostream>
using namespace std;
int main () {
	int a, b;
	string ans;
	char temp[32] = {0};
	scanf ("%d%d", &a, &b);
	int c = a + b;
	sprintf(temp, "%d", c);
	ans = temp;
	for (int i = ans.length() - 1, count = 1; i > 0; i--, count++)
		if (count % 3 == 0 && ans[i - 1] != '-')
			ans.insert(i, 1, ',');
	printf ("%s", ans.data());
	return 0;
}

THINKING AND NOTICE

1. Insert a comma every 3 character.

2. Traversal the string from the end of it.

3. If the result of a+b is negative, check that there are no negative sign - before inserting a comma,.

REFLECTION AND COMMENTS

• Relatively easy.
• Hope that I can stick to using English to write articles.