How do you use a pointer?

Answer 1

A pointer is a reference to a location in memory that is a primitive type in C and other low-level languages.

An example use would be if you wanted to store data at run-time, you would have to allocate memory using the malloc function, an you would access that memory area using a pointer

Example (modified from http://www.cplusplus.com/reference/clibrary/cstdlib/malloc):

#include <stdio.h>

#include <stdlib.h>

int main ()

{

int i,n;

char * buffer; // Declare a pointer to a char

printf ("How long do you want the string? ");

scanf ("%d", &i); // Get input from user and store in i

// Allocate space for i+1 characters

buffer = (char*) malloc ( sizeof( char[i+1] ) );

// buffer should now contains a pointer to this location

if (buffer==NULL)

exit (1); // Memory allocation failed, abort

for (n=0; n<i; n++)

buffer[n]=rand()%26+'a'; buffer[i]='\0';

printf ("Random string: %s\n",buffer);

free (buffer); // Release allocated memory return 0;

}