Question about for and while loop

Orlando Stevenson

Hello dear mates!

I am beginner at programming and have some doubts about loops. Okay, here goes little program:

private void button4_Click(object sender, EventArgs e)
{
int count = 0;

while (count < 10)
{
count = count + 1;
}

for (int i = 0; i < 5; i++)
{
count = count - 1;
}

MessageBox.Show("The answer is " + count);
}

Now here is the problem. I can not figure out why is the final result of this program 5? I have tested the while loop only to see what it will print out and it was only a number of 10. Why it did not print all numbers from 1 to 9 because count is 0 and there is condition that after every loop value increases by one until count is less than 10?

After that I have only tested for loop and its result was -5 and I really do not know why. Can someone enlighten me?

Final result of this program is 5 probably because the result of while loop which is 10 and the result of for loop which is -5 are subtracted. Why are they subtracted? Where is that part in the program?

Thank you mates in advanced!

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Orlando Stevenson15y ago
Thank you Vulpes. I think I understand now.
Vulpes15y ago
Well, the for loop on its own reduces the value of count by 5.

So, if you comment out the while loop, count which starts off at 0 will end up as -5.

My last sentence was only talking about the for loop which decrements (i.e. reduces by 1) the count variable on each of its five iterations.
Orlando Stevenson15y ago
Thanks mate for helping! Things are a bit brighter now. Can you tell me why would for loop only produce the result of -5? And the second question, I will quote you: "Each time through the loop, the count variable will be decremented by one." Do you speak about for loop?
Vulpes15y ago
The while loop continues to execute whilst the value of the variable, count, is less than 10.

Initially, count is 0 and is incremented by one each time through the loop. Consequently, after 9 iterations its value will be 9 and the loop will then execute for the tenth and last time, leaving count with a value of 10.

The for loop will execute as long as the iteration variable i is less than 5. Initially, i is 0 and so the loop will execute 5 times finishing when i equals 4.

Each time through the loop, the count variable will be decremented by one. So, as it starts at 10, it will end up at 5 which is what the MessageBox shows.