1001 A+B Format

description

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

idea

• 实现目标：把整数自低位到高位，每隔三个加一个逗号
• 根据位数规律输出，联想到借助字符串

solution

#include <stdio.h>
#include <string.h>
int main(){
	int a, b;
	char result[10], flag[10] = {0}, n = 0;
	scanf("%d%d", &a, &b);
	sprintf(result, "%d", a+b);
	for(int i = strlen(result) - 1; i >= 0; i--){
		if(n == 3){
			n = 1;
			flag[i] = 1;
		}
		else
			n++;
	}
	for(int i = 0; i < strlen(result); i++){
		printf("%c", result[i]);
		if(result[i] != '-' && flag[i]) printf(",");
	}
	return 0; 
} 

可以哭，可以难受，但不能停止走出舒适区的行动。因为想让人生的底色是进步，而非自证预言的憾事。