why does my c++ code below results to 35 instead of 25...?

Question

#include <iostream>
using namespace std;

int main()
{
int num = 1;
int n = 0;
while (num < 10) {
cout << "Number: " << num << endl;
num = num + 2;
n = n+num;
}
cout << "Total = " << n;

return 0;
}

Answer 1

Lets modify your code little bit as you are adding num to n after modification in value of n not before modification in its value
See output for below code(see values of num getting printed) to get why result is coming 35.

#include <iostream>
using namespace std;
int main()
{
int num = 1;
int n = 0;
while (num < 10) {
num = num + 2;
cout << "Number: " << num << endl;
n = n+num;
}
cout << "Total = " << n;

return 0;
}

Answer 2

Your program is perfect, but since you used "while " for checking condition ; the last check when num greater than 10 will be included. So just change the line of condition to the following:
While (num < 9)
You will get the right output 25