68 lines
1.5 KiB
C
68 lines
1.5 KiB
C
/* An example of
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Creating dynamically an array
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Populating the array
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Displaying the contents
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Freeing up the memory
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Version 3 : Read and Write values using pointers
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*/
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#include <stdio.h>
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#include <stdlib.h>
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int main(void)
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{
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int *ipArray = NULL; /* Create the pointer and set */
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/* to null to start with */
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int *ipStartValue = NULL; /* A place to store ipArray's */
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/* initial value ,ie ipArray[0] */
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int iSize = 0; /* Define our 'size' variable */
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int i; /* A Loop variables */
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/* Prompt for array size */
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printf("\nHow big is the array to be ? ");
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scanf("%d",&iSize);
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/* Allocate the memory */
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ipArray = (int *)calloc(iSize, sizeof(int));
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if ( ipArray == NULL )
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{
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printf("\nUnable to allocate the memory requested");
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printf("\n ** Program terminating ** \n");
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exit (1);
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}
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/* Store the base memory address for use later */
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ipStartValue = ipArray;
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/* Populate the array (Method 2 - Use Pointers: This is much faster !) */
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for ( i = 0 ; i < iSize ; i++ )
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*ipArray++ = iSize - i;
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/* Reset the pointer to the origin of the array */
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ipArray = ipStartValue;
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/* display the data */
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for ( i = 0 ; i < iSize ; i++ )
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printf("Value %d is %d\n",i,*ipArray++ );
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/* free memory : Again, reset ipArray to its origin */
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ipArray = ipStartValue;
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free(ipArray);
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/* The above two lines could be replaced with free (ipStartValue) */
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return 0;
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}
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