Passing pointer to function - Objective C

Objective C programming language allows you to pass a pointer to a function. To do so, simply declare the function parameter as a pointer type.

Following a simple example where we pass an unsigned long pointer to a function and change the value inside the function which reflects back in the calling function:

#import <Foundation/Foundation.h>

@interface SampleClass : NSObject
     
          - (void) getSeconds : (int *) par; 
@end

@implementation SampleClass

   

      - (void) getSeconds : (int *) par

        {

              *par = time(NULL);

         }

@end

int main()

{

     SampleClass *obj = [[SampleClass alloc]init];

     [obj getSeconds : &sec ];

     

     // print the actual value

    NSLog (@:Number of seconds : %d\n", sec);

     return 0;

}        

 

The function, which can accept a pointer , can also accept an array as shown in the following example.

#import <Foundation/Foundation.h>

@interface SampleClass : NSObject
     
          - (double) getAverage : (int *) arr ofSize : (int) size; 
@end

@implementation SampleClass

   

      - (double) getAverage : (int *)arr ofSize : (int) size

        {
                 int i, sum = 0;
                 double avg;
                
                 for( i = 0; i <size; i++)
                 {
                        sum = sum + arr[i]
                  }
                   avg = (double)sum /size;
              return avg;

         }

@end

int main()

{
      int balance[5] = {1000, 2, 3, 17, 50};
      double avg;
 

     SampleClass *obj = [[SampleClass alloc]init];

 
        avg = [obj getAverage: balance ofSize: 5];

     

     // print the actual value

       NSLog (@"Average  of value is : %f\n", avg);

      return 0;

}        

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