Thread: just stop working when compile...

Ok one last fixup....

for(b=2;b<=N-1;b++)

is the same as

for(b = 2; b < N; b++)

if N == 5 then N - 1 = 4 so <= makes it exit on 4, returning false on 5. b < N will return true for values 0 .. 4 and false on 5 ...

It may not seem like much of a difference for relatively small values of N but the <= N -1 adds in a bit of extra code -- suptracting 1 from N and doing 2 comparisons every time-- that will amount to a performance difference on larger values... It could make a difference of minutes if you asked for the first 10,000,000 prime numbers.

the loop is about the sieve of Eratosthenes...i dont know if you heard about that,its method which separates prime numbers from all other numbers...

this loop is okay because this code works fine without dynamic allocation memory,but when i used it compiler start to show message stop working...

for input N = 3,

Code:

    for(b=2;b<=N-1;b++) {       // 2 <= 3-1 is true proceed...
       v=b;
       if(*(p+v)==0) {                             
	   printf("%d ", b);
	      for (i=2;v<=N-1;i++) {
	         v=b*i;                  //1 pass. N= 3, b = 2,i=2, v = 4; p is allocated only 3 int.and you write to *(p+4)!
	         *(p+v)=1;	   	      	      }                                                
       }		       
    }

i still dont get what should i do... i tried -1,+1,stay the same...

whatever i put is still put message stop working...

code and loops works fine...look this code without dynamic allocation...

Code:

#include<stdio.h>
#include<stdlib.h>

int main() {
    int *polje=NULL,N,v,b,i;   
    int k[1000]={0};                             
    printf("Enter num elements:");
    scanf("%d",&N);
    

 
     
    for(b=2;b<=N;b++) {
       v=b;
       if(k[v]==0) {
	   printf("%d ", b);
	      for (i=2;v<=N;i++) {         
	         v=b*i;              
	         k[v]=1;	   	       
	      }                                                 
       }		        
    }				
    
    printf("\nEND");
    
    getch();
    return 0;
}

this is the same code and loops but without dynamic allocation and all works fine...
sorry all for your time... but i really dont know where is mistake... and i KNOW that it is not in loop because its the same as in this code... its somewhwere in dynamic allocation... but i dont know where...

thank you all for your help till now...and in advance..

thanks laserlight...

with your piece of code it works...and compiler is quiet...

thanks...

Originally Posted by notcodemonkey

code and loops works fine...look this code without dynamic allocation...

When it asks for the number of elements, try putting in 1001 ...

CommonTater that is not the point...i know that...
i will be honest...i still dont get it...why my loop doesnot work...

laserlight if you have a minute i would really be thankfull if you could explain why is your loop working and mine not...

thanks all of you...and specially to laserlight...