Pointer to pointer

A pointer variable in C language can also contain address of another pointer variable. This concepts is called pointer to pointer. We can declare a pointer to pointer as:
int **ptr;
Here, ptr is a pointer to pointer.

Program

#include<stdio.h>
int main()
{int var1=20,*var2,**ptr;var2=&var1;

ptr=&var2;

printf(“\n*ptr=%u”,*ptr);
printf(“\n**ptr=%d “,**ptr);

return(0);
}

Output

*ptr=65524
**ptr=10

Description

In the above program, ptr is pointer to pointer. It contains address of aother pointer variable var2 which contains the address of variable var1.
*var2 refers to the value of var1.
*ptr refers to the address of var1.
**ptr refers to the value of variable var1.

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Lesson tags: pointer to pointer, program of pointer to pointer in c

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