咸鱼哥学算法1001 A+B Format (20分)

刺骨的言语ヽ痛彻心扉 2023-02-28 12:55 68阅读 0赞

**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 ![−106 ≤a,b≤106][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

**题目解释：**  
给出两个不同的数字A和B，其中A、B都在int范围之内，将他们相加，并按照标准格式输出。即从每隔三位输出一个逗号，这符合科学计数的模式。

**解题思想：**  
1）因为A和B相加不会溢出，因此直接相加；  
2）将相加之后的和转换为字符串，由此得到和的长度；  
3）以样例为例，-999991，下标位置从左到右依次是0-1-2-4-5-6，字符串长度为7,每三位输出一个逗号，因此，对下标和长度取余数，余数相等的位置就是输出逗号的位置。

**代码：**

//1001 A+B Format (20分)
    #include <iostream>
    #include <cstring>
    using namespace std;
    int main()
    {
        
    	int a, b, c;
    	scanf("%d %d", &a, &b);
    	string ans = to_string(a + b);
    	int len = ans.length();
    	for(int i=0; i<len; i++)
    	{
        
    		printf("%c",ans[i]);
    		if(ans[i] == '-')
    			continue;
    		if((i+1)%3 == len%3 && i <len-1)
    			printf(",");
    	}
    	return 0;
    }

**输出结果：**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTg4NTIzMg_size_16_color_FFFFFF_t_70]

[10_6_ _a_b_10_6]: /images/20230209/5aaff874a1af4b75b55b9a79179fc1fb.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTg4NTIzMg_size_16_color_FFFFFF_t_70]: /images/20230209/22f4e36a32ce4e0d840da9cec9250e72.png