“if 块”在这段代码中是如何工作的？

Question

Please consider the following code:

#include <iostream>

using std::cin;
using std::cout;
using std::endl;

int main() {
    int a, b;
    cout << "Enter two integer: ";
    cin >> a >> b;

    if (a > b) {
        int temp = a;
        a = b;
        b = temp;
    }
    cout << a << "<=" << b << endl;
}

The above code yields the minimum of the two inserted numbers. Can anyone explain how the if block works?

Answer 1

It's the idiomatic way of swapping two numbers.

There are more efficient ways: to exploit those use std::swap instead.

(The statement int temp=a; sets the variable temp to the value of a . The statement a=b; sets a to the value of b . Finally, b=temp; sets b to temp which was the original value of a . The overall effect therefore is to exchange the values of a and b .)