[Solved] Segmentaion fault in C

by


int *ptr; is a pointer to an interger, but you never initialized it. The value of ptris not defined so this is undefined behavior. To make your code work, the value of ptr has to be an address of a variable with type int. *ptr and **p_ptr tries to read the value where ptr refers to and this causes the segmentation fault. Adapt your code like this:

main()
{
  int myInt;               // local varibale myInt
  int *ptr = &myInt;       // pointer ptr refers to local varibale myInt
  init(&ptr);              // pass pointer to ptr to function init
  printf(" %d \n",*ptr);
}

Note in function init, p_ptr now is a pointer to ptr and so a pointer to a pointer to myInt.

Of course you can allocate dynamic memory too:

#include <malloc.h>

main()
{
    int *ptr = &myInt = malloc( sizeof( int ) ); // ptr refers to dynamicly allocated memory
    init(&ptr);             
    printf(" %d \n",*ptr);
    free( ptr );                                 // free the dynamic memory
}

solved Segmentaion fault in C