PAT (Advanced Level) Practice 1001 A+B Format

1001 A+B Format (20 分)

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

#include<iostream>
#include<cmath>
using namespace std;

int a[10];
char b[20];
int main()
{
	int n,m,j,k,i,T;
	int A,B,c;
	cin>>A>>B;
	c = A+B;
	bool flag;
	c>=0?flag=false:flag=true;//flag代表是否插入负号 
	
	c = abs(c);
	if (c==0) //特判 
	{
		cout<<"0"<<endl;
		return 0;
    }
	
	
	j=0;
	
	while (c)
	{
		a[j++] = c%10;
		c/=10;
	}
	
	int sum=0;
	int t=0;
	for (i=0;i<j;i++)
	{
		sum++;
		b[t++] = a[i]+'0';
		if (sum==3 && (i+1<=j-1))
		{
			b[t++] = ',';
			sum=0;
		}
	}
	if (flag)
	cout<<"-";
	
	for (i=t-1;i>=0;i--)
	cout<<b[i];
	cout<<endl;
	
	return 0;
}