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 −. 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题解：这里所说的每三个数字中间添加一个‘，’是指从右边的第一个数字开始数，每三个数字添加一个‘，’。有时间的话还是要把那本《C++ prime plus》再看一遍，很多C++的基础语法都忘了=_=
#include<iostream>
using namespace std;
int main() {
int a, b;
cin >> a >> b;
string s = to_string(a+b);
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 << ',';
}
cout << endl;
return 0;
}
2021-01-28
map() 会根据提供的函数对指定序列做映射。
map(function, iterable, ...)第一个参数 function 以参数序列中的每一个元素调用 function 函数，返回包含每次 function 函数返回值的新列表。
Python3 range() 函数返回的是一个可迭代对象（类型是对象），而不是列表类型， 所以打印的时候不会打印列表。
range(stop)range(start, stop[, step])
a = str(sum(list(map(int, input().split())))) count = 0 for i in range(len(a) - 1, 0, -1): count += 1 if count % 3 == 0 and a[i-1] != '-': a = a[:i] + ',' + a[i:] print(a)