[SOLVED] countdown loop problem in c

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adrian.eremencu

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Hi,
I have a problem with the following loop in C. It's a countdown for 4 digits(mm:ss).

Code C - [expand]
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void countdown(void)  // the countdown
{
  while ( min2 >= 0)
  { 
    while (min1 >= 0)
    {
      while (sec2 >= 0)
      {
    while ( sec1 >=0)
    {
      sec1--;
      delay_1s();
    }
    sec1 = 9;
    sec2--;
    }
    sec2 = 5;
    sec2--;
  }
  min1 = 9;
  min2--;
 }
}


For example: if i have the values 15:30 (mm:ss) it decreases the sec2 val until is less than 0, then the value of sec2 is changed to 9 and sec1 is decreased by 1, and this process continues until all digits are = 0. The countdown works but when it reaches 00:00 it doesn't stop.
 

Depending on unsigned/signed variable type, countdown will either never stop (>=0 is always true for an unsigned number) or stop when reaching negative values. That's how you wrote the code.
 
Reactions: tpetar

    tpetar

    Points: 2
    Helpful Answer Positive Rating
I used signed var. But i think i know why it doesn't stop.
Let's say that i have 00:02. The procces will be the following:
00:02
00:01
00:00 and then when the sec1 is lower than 0 it exits the loop and automatically becomes 9, the sec2 becomes 5 and the min1 becomes 9 and in my main before i call this function i have while ( (min2 != 0) || (min1 != 0) || (sec2 != 0) || (sec1 != 0)), therefore the loop begins again. I will change the while loop in my main with an if statement and that should solve my problem.

- - - Updated - - -

It works now. Thank you for the support.
 

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