C++ Primer Plus第六版编程练习---第5章 循环和关系表达式

#include <iostream>

int main()
{
    int startNum = 0;
    int endNum = 0;
    std::cout << "please enter tow num:" << std::endl;
    std::cin >> startNum;
    std::cin >> endNum;

    long long sum = 0;
    for(int i = startNum; i <= endNum; i++)
        sum += i;

    std::cout << "the sum betwen " << startNum << " and " << endNum << "is: " << sum << std::endl;
    return 0;
}