Question

Why this C++ code output is

1

1

num is 3

Can u explain to me? Thank u

code:

#include 

using namespace std;

void xFunction(int num)
{
    do
    {
        if (num % 2!= 0)
            cout << num << " ";
        num--;
    }
    while (num >=1);
    cout << endl;
}

int main() {
    int num = 1;
    while (num <= 2)
        {
        xFunction(num);
        ++num;
        }
    cout << "num is " << num;
    return 0;
}

Answer 1

first main function exicute with value of num=1
then while loop exicute for num=1 means while(1<=2) so condition is true and loop exicuted, after exicution of loop function will be call with value num=1
after function calling function defination will be exicuted then exicute do while loop which is inside of function after first iteration of do while loop exicute if satatement if(1%2!=0) ,statement is true so print 1 and value of num decrement with 1 so new new value of num will be 0
then check do while condition while(0>=1) ,condition is false so loop will be terminate and print new line and function terminate and compiler will goes to main and exicute other satement of main then exicute
++num and value of num will be 2 because num is a local variable so value of num no change in calling function, again while loop exicute for num=2 means while(2<=2) so condition is true and again function will be call with value num=2
after function calling function defination will be exicuted then exicute do while loop which is inside of function after first iteration of do while loop exicute if satatement if(2%2!=0) ,statement is false so direct go to num-- and value of num will be decrement with 1 so new new value of num will be 1
then check do while condition while(1>=1) ,condition is true so again exicute loop then exicute if satatement if(1%2!=0) ,statement is true so print 1 and value of num decrement with 1 so new new value of num will be 0 then check do while condition while(0>=1) ,condition is false so loop will be terminate and print new line and function terminate and compiler will goes to main and exicute other satement of main then exicute
++num and value of num will be 3 because num is a local variable so num variable no change in calling function again while loop exicute for num=3 means while(3<=2) so condition is false so loop will be terminate and print 3

so output :
1
1
3