利用while循环

#include <iostream>

int main()

{

int sum = 0, val = 50;

while (val <= 100)

{

sum = sum + val;

++val; //++val先加后用

}

std::cout << "sum of 50 to 100 inclusive is " << sum << std::endl;

return 0;

}

下面是for循环

#include <iostream>

int main()

{

int sum = 0, val = 50;

for (; val <= 100; val++) //val++表示先用后加

{

sum = sum + val;

}

std::cout << "sum of 50 to 100 inclusive is " << sum << std::endl;

return 0;

}