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Random Time Delay in C

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ninnymoggin

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I want to put a delay in my code to wait for a random number of seconds before going forward. I'm new to C and coding in general so I tried to patch together two example functions I found (random and delay), but so far it's not working. This is what I have so far:


Code:
 // generate a random number between 1 and 5
int random() 
{ 
    int i; 
    for (i = 0; i < 1; i++) { 
        int num = (rand() % 
           (5 - 1 + 1)) + 1; 
        return num; 
    } 
} 
  
//wait x number of seconds
void delay(int number_of_seconds) 
{ 
    // Converting time into milli_seconds 
    int milli_seconds = 1000 * number_of_seconds; 
  
    // Storing start time 
    clock_t start_time = clock(); 
  
    // looping till required time is not achieved 
    while (clock() < start_time + milli_seconds); 
} 
  


main(void) {
    init_elecanisms();
    
    
    while (1) {
        if (start==0){
            int t = random();       //t=random number betwen 1 and 5
            delay(t);               //delay for random number of seconds
            led = ON;
            LED2 = (p1 == 0) ? ON : OFF; 
            l1 = (SW3 == 0) ? ON : OFF; 
        }
    }    
}
 

what contoller compiler are you using?

1)your for() loop execute only once.

what is the rand() output range ?
in standard c it may be anything from 0 to 32k.

dividing by 5 , you may get a max of 6000 approx.
equivalent remainder of 2000(approx) seconds in your timedelay routine.

and you are conveting it into milliseconds and waiting for that time.
 
Last edited:

I'm using scons (is that a compiler, idk I'm a noooob).

I got rid of the for() loop in random() because I only want to generate one number, and set the range to 6 (I think) so it looks like this now:
Code:
int random() 
{ 
    int num; 
    num = rand() % 6; 
    return num;  
}

The code runs but there's no delay.
 

ok.scons is software construction tool -not a compiler.
which controller are you targetting and its compiler?
 

I don't know what you're asking me, could you try rephrasing it as if I were a five year old?
 

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