n C++17 and above, the evaluation order of function arguments is guaranteed to be
left-to-right. This means that if a function is called with multiple arguments, 
the expressions for those arguments will be evaluated in the order they appear
in the function call, from left to right.

Here's an example:

c
Copy code
#include <iostream>

int foo(int a, int b) {
    std::cout << "a: " << a << " b: " << b << std::endl;
    return a + b;
}

int main() {
    int x = 1;
    int y = 2;
    int z = 3;

    // The expressions for the function arguments are evaluated in the order they appear
    int result = foo(x, y + z); // a: 1 b: 5

    std::cout << "result: " << result << std::endl;
    return 0;
}
In this example, the expressions x and y + z are evaluated before they are passed 
as arguments to the foo function. The std::cout statement inside the function
prints "a: 1 b: 5" to the console, indicating that the expression y + z was
evaluated before the expression x. And the final result is 6.