Programming in C

238 Chapter 11 Pointers

Program 11.2 illustrates some interesting properties of pointer variables. Here, a

pointer to a character is used.

Program 11.2 More Pointer Basics

// Further examples of pointers

#include <stdio.h>

int main (void)

{

char c = 'Q';

char *char_pointer = &c;

printf ("%c %c\n", c, *char_pointer);

c = '/';

printf ("%c %c\n", c, *char_pointer);

*char_pointer = '(';

printf ("%c %c\n", c, *char_pointer);

return 0;

}

Program 11.2 Output

Q Q

/ /

( (

The character variable cis defined and initialized to the character 'Q'. In the next line

of the program, the variable char_pointeris defined to be of type “pointer to char,”

meaning that whatever value is stored inside this variable should be treated as an indirect

reference (pointer) to a character. Notice that you can assign an initial value to this vari-

able in the normal fashion.The value that you assign to char_pointerin the program is

a pointer to the variable c, which is obtained by applying the address operator to the

variable c. (Note that this initialization generates a compiler error if chad been defined

afterthis statement because a variable must always be declared beforeits value can be ref-

erenced in an expression.)

The declaration of the variable char_pointerand the assignment of its initial value

could have been equivalently expressed in two separate statements as

char *char_pointer;

char_pointer = &c;