Pointers and arrays in c

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Pointers and arrays in c

Before we understand the concept of arrays of pointers, let us consider the following example, which makes use of an array of 3 integers:

#include <stdio.h>
 
const int MAX = 3;
 
int main ()
{
   int  var[] = {10, 100, 200};
   int i;
 
   for (i = 0; i < MAX; i++)
   {
      printf("Value of var[%d] = %d\n", i, var[i] );
   }
   return 0;
}

When the above code is compiled and executed, it produces the following result:

Value of var[0] = 10
Value of var[1] = 100
Value of var[2] = 200

There may be a situation when we want to maintain an array, which can store pointers to an int or char or any other data type available. Following is the declaration of an array of pointers to an integer:

int *ptr[MAX];

This declares ptr as an array of MAX integer pointers. Thus, each element in ptr, now holds a pointer to an int value. Following example makes use of three integers, which will be stored in an array of pointers as follows:

#include <stdio.h>
 
const int MAX = 3;
 
int main ()
{
   int  var[] = {10, 100, 200};
   int i, *ptr[MAX];
 
   for ( i = 0; i < MAX; i++)
   {
      ptr[i] = &var[i]; /* assign the address of integer. */
   }
   for ( i = 0; i < MAX; i++)
   {
      printf("Value of var[%d] = %d\n", i, *ptr[i] );
   }
   return 0;
}

When the above code is compiled and executed, it produces the following result:

Value of var[0] = 10
Value of var[1] = 100
Value of var[2] = 200

You can also use an array of pointers to character to store a list of strings as follows:

#include <stdio.h>
 
const int MAX = 4;
 
int main ()
{
   char *names[] = {
                   "Zara Ali",
                   "Hina Ali",
                   "Nuha Ali",
                   "Sara Ali",
   };
   int i = 0;

   for ( i = 0; i < MAX; i++)
   {
      printf("Value of names[%d] = %s\n", i, names[i] );
   }
   return 0;
}

When the above code is compiled and executed, it produces the following result:

Value of names[0] = Zara Ali
Value of names[1] = Hina Ali
Value of names[2] = Nuha Ali
Value of names[3] = Sara Ali

 

 

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