c program - swap using pointers

The following code will produce segmentation fault error due to the uninitialized pointer.

int swap(int* x, int* y)
{
    int *t;
    *t = *x;
    *x = *y;
    *y = *t;
    return 0;
}

corrected code is as follows, 

int swap(int* x, int* y)
{
    int t;
    t = *x;
    *x = *y;
    *y = t;
    return 0;
}

completed working code,

#include<stdio.h>

int swap(int*,int*);

int main()

{

    int a, b;

    printf("Enter value for a and b: ");

    scanf("%d %d", &a, &b);

    printf("\nValues before swap a=%d and b = %d", a, b);

    swap(&a, &b);

    printf("\nValues after swap a=%d and b = %d", a, b);    

}

int swap(int* x, int* y)
{
     int t; 

    t = *x;
    *x = *y;
    *y = t;
    return 0;
}