How to print variable addresses in C?

When i run this code.

#include <stdio.h>

void moo(int a, int *b);

int main()
{
	int x;
	int *y;

	x = 1;
	y = &x;

	printf("Address of x = %d, value of x = %d\n", &x, x);
	printf("Address of y = &d, value of y = %d, value of *y = %d\n", &y, y, *y);
	moo(9, y);
}

void moo(int a, int *b)
{
	printf("Address of a = %d, value of a = %d\n", &a, a);
	printf("Address of b = %d, value of b = %d, value of *b = %d\n", &b, b, *b);
}

I keep getting this error in my compiler.

/Volumes/MY USB/C Programming/Practice/addresses.c:16: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘int *’
/Volumes/MY USB/C Programming/Practice/addresses.c:17: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘int **’
/Volumes/MY USB/C Programming/Practice/addresses.c:17: warning: format ‘%d’ expects type ‘int’, but argument 3 has type ‘int *’
/Volumes/MY USB/C Programming/Practice/addresses.c: In function ‘moo’:
/Volumes/MY USB/C Programming/Practice/addresses.c:23: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘int *’
/Volumes/MY USB/C Programming/Practice/addresses.c:24: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘int **’
/Volumes/MY USB/C Programming/Practice/addresses.c:24: warning: format ‘%d’ expects type ‘int’, but argument 3 has type ‘int *’

Could you help me?

Thanks

blargman

You want to use %p to print a pointer. From the spec:

> p The argument shall be a pointer to void. The value of the pointer is converted to a sequence of printing characters, in an implementation-defined manner.

And don't forget the cast, e.g.

printf("%p\n",(void*)&a);

When you intend to print the memory address of any variable or a pointer, using %d won't do the job and will cause some compilation errors, because you're trying to print out a number instead of an address, and even if it does work, you'd have an intent error, because a memory address is not a number. the value 0xbfc0d878 is surely not a number, but an address.

What you should use is %p. e.g.,

#include<stdio.h>

int main(void) {

    int a;
    a = 5;
    printf("The memory address of a is: %p\n", (void*) &a);
    return 0;
}

Good luck!

To print the address of a variable, you need to use the %p format. %d is for signed integers. For example:

#include<stdio.h>

void main(void)
{
  int a;

  printf("Address is %p:",&a);
}

Looks like you use %p: Print Pointers

I tried in online compiler https://www.onlinegdb.com/online_c++_compiler

int main()
{
    cout<<"Hello World";
    int x = 10;
    int *p = &x;
    printf("\nAddress of x is %p\n", &x); // 0x7ffc7df0ea54
    printf("Address of p is %p\n", p);    // 0x7ffc7df0ea54

    return 0;
}