#include<iostream> using namespace std; int main() { int i; int count = 0; cout << "请输入一个正整数: "; while (cin >> i&&cin.get() == 'n') { if (i <= 0)cout << "请输入一个......
Consider the natural numbers from 1 to N. By associating to each number a sign (+ or -) and calculating the value of this expression we obtain a sum S. The prob...