Objective-C
Objective-C is an object-oriented programming language developed in the mid-1980s by engineers Brad Cox and Tom Love. It is based on the C programming language and uses a system of message passing derived from the programming language Smalltalk. Objective-C was licensed by NeXT in 1988 and is the programming language used with Apple software today.
What is different about Objective-C?
In Objective-C, OOP (object-oriented programming) is based on passing messages between object instances. Unlike other OOP languages where you call the method of an instance to invoke its behavior, in Objective-C, you send it a message. The two types of programming are more or less equivalent, but there are differences. For example, a message sent to an object in Objective-C can be ignored or forwarded to another object, rather than returning a value.
Here is an example "Hello, World!" program written in Objective-C:
#import <stdio.h>
#import <foundation foundation.h="">
int main(void)
{
NSLog(@"Hello, world!\n");
return 0;
}