Regarding array operations using pointers.....

[abhinuke]

I am trying to print prime numbers from 1 to 100. I am passing an array to a function and then zeroing all the elements which are multiples of 2,3,5. When I compile the code,I am getting all the memory addresses as an output. Here is the code that I have written.

#include <stdio.h>
#include <stdlib.h>
#define size 100
int main()
{
    int i,a[size];
    int prime(int *,int);
 
    for(i=1;i<size+1;i++)
    {
        a[i]=i;
    }
    printf("Before procedure the array is\n");
    for(i=1;i<size+1;i++)
    {
 
        printf("%d\n",a[i]);
    }
    prime(&a[0],size);
 return 0;
}
int prime(int *ptr,int j)
{
    int k;
    ptr++;
    for(k=1;k<j+1;k++)
    {
        if(*ptr==2||*ptr==3||*ptr==5)
        {
            break;
        }
        else
        {
            if(*ptr%2==0||*ptr%3==0||*ptr%5==0)
            {
                *ptr=0;
            }
        }
        ptr++;
    }
 
ptr=ptr-99;
    printf("Array after removal\n");
 
    for(k=1;k<j+1;k++)
    {
        if(*ptr==0)
        {
            break;
        }
        else
        {
            printf("%d\n",*ptr);
 
        }
        ptr++;
    }
}
 

Further can I anyone of the moderators enlighten me on pointer arithmetic in context of arrays and functions. I have read arrays revealed article but it didn't give me much information.

[mayankarpit]

He is not printing adrress. infact he is printing garbage values. this is happening bcoz of break stament at line 30. As soon as *ptr == 2 u break from for loop and do ptr = ptr - 99. Bcoz of this ptr starts pointing some garbage location so when loop stars at line 45 it start with printing garbage values

[abhinuke]

Thanks.Worked fine.I guess I'll have to revise break keyword again.
Had to manipulate some &&,|| operators.

[swatib2k101]

I have one pointer to string ,
char *str[4];
i am calling str[1] in a func say make func()
How to do it.Seg fault is coming.
char *str[4];
makefunc(&str);

char makefunc(char *pr[])
How to do it?Please help
Basically I want to call this str[1] in other function and prints its value.

[akshayshukla]

You can call function like this.
makefunc(&pr[1]));

and define function like this.
char makefunc(char *pr)
{
printf("Passed value is %d", *ptr);
}

[mayankarpit]

Solution suggested by akshay will not solve the segv.Yo have declared a array of char. pointer & before paasing to function you never initialsed it.

[akinidu]

@akshayshukla
WHy dont u post the revised code tooo