Question

I am trying to solve this and i came up with this

#include <stdio.h>
#define primeLimit 100000

int prime (long int Start2,  long int Stop2 )
{
    long int a[primeLimit];
    long int i,j,k,l;
    for (i=Start2;i<=Stop2;i++) {
        a[i] = 1;
    }
    for (i=Start2;i<=Stop2;i++) {
    if (a[i]!= 0 && i!=1) {
        for (j=2; j*j< i;j++) {
            if(i%j==0)
                break;
        }
        if(j*j > i) {
            printf(" \n %d",i);
            l = i;
            for (k = i*i; k< Stop2;) {
                a[k] = 0;
                k = k+l;
            }
        }
        else {
            a[i] = 0;
        }
    }
}

return 0;
}

int main(void)
{
    long int start,stop,a,look;
    scanf("%ld", &look);
    for (a=1;a<=look;a++) {
        scanf("%ld %ld", &start,&stop);
        prime (start,stop);
    }
    return 0;
}

I am using GNU GCC compiler, CodeBlocks IDE on 32 bit windows 7 PC. The code was fine when i ran it on my compiler. But when submitted it shows runtime error (SIGSEGV) .Can anyone point me out where i am going wrong/how to do it better?

Thank you

Answer 1

The allowed inputs range from 1 to 1000000000, but your array only has 100000 elements .. the difference between the two inputs. You should be indexing it with i-Start2 or k-Start2, not i or k. And you need a[primeLimit+1], because you need to access a[Stop2-Start2], i.e., a[100000].