printf、cout调用参数顺序的理解误区

#include <iostream>
#include <string>
#include <stdio.h>
using namespace std;
//参数的调用顺序是从右向左
int test1()
{
    cout << "test1" << endl;
    return 1;
}

int test2()
{
    cout << "test2" << endl;
    return 2;
}

int main()
{
    int i = 3;
    //先执行右边的i++,再执行左边的i 但是显示的时候，按"i = %d,i++ = %d\n"的顺序显示
    printf("i = %d,i++ = %d\n",i,i++); //显示: i = 4,i++ = 3
    i = 3;
    printf("i = %d,i++ = %d,i++ = %d\n",i,i++,i++); //显示: i = 5,i++ = 4,i++ = 5

    //先执行右边的test2(),再执行左边的test1() 但是显示的时候，按"%d,%d\n"的顺序显示
    printf("%d,%d\n",test1(),test2());

    //先执行右边的test2(),再执行左边的test1() 但是显示的时候，按顺序显示
    cout << test1() << " " << test2() << endl;

    return 0;
}