[Practice 16.2] Why does my code only output 0?

Question

Hello, forgive me if this is a dumb question. I’m still confused on what the ‘while’ statement does.

Practice 16.2 wants to make a countdown, it goes something like this:

Sample:
5
Output:
5
4
3
2
1
0

This is my code:

#include <iostream>
using namespace std;

int main()
{
int seconds;
cin>>seconds;

//your code goes here
while (seconds >0)
seconds--;
cout << seconds;

return 0;
}

In my mind, I’m expecting the computer to take the given integer and minus it by 1 till it reaches 0, with the last deduction being ‘1-1’; whilst outputting each calculated number. However the PC just outputs 0 instead. Any help would be appreciated, just don’t give me the answer directly! Thanks :)

Answer 1

You actually aren't meant to use a do-while loop here as it isn't taught for a few more lessons. A simple while loop is enough to pass.

int main() {
int seconds;
cin >> seconds;

while(seconds > -1) {
cout << seconds-- << endl;
}
return 0;
}

Answer 2

Plaush

Because you are printing value outside the while loop. When you don't use curly brackets {} then statement will be of single line statement.

It should be like

while (seconds > 0) {
seconds--;

cout << seconds;
}

Answer 3

Don't forget the curly braces for your while statement.

while () {
// Your code here
}

Answer 4

Plaush

You have to use do while loop here

#include <iostream>
using namespace std;

int main() {
int seconds = 0;

cin >> seconds;

do {
cout << seconds << endl;
seconds--;
} while (seconds >= 0);

return 0;
}

Answer 5

ChaoticDawg That’s what I did, haha. I just misseed out ‘endl’. Thanks for the answer, though! :)

Answer 6

Zeke Williams It didn’t work. It stopped outputting 0s but it’s now outputting a bunch of random numbers, ranging from 10 to ~200

Answer 7

I Am AJ ! Thank you so much! They didn’t teach me the ‘do’ function, or maybe i just missed it. No pun intended, what does the ‘do’ function do exactly?

Does it execute the cout function while the ‘while’ function is running?

Edit: I’ve found my orignal error, I missed out ‘endl’. As a result, it didn’t end the line and just printed the results in one line