Foundation Framework in Objective-C

Foundation Framework and Their Types

The Foundation Framework serves as the essential building block for your applications, providing fundamental components and guidelines. It offers a comprehensive library that introduces common data types frequently utilized in applications, such as String, Files, Date, Timer, Thread, and others. This framework facilitates memory management, serialization, localization, networking, and more, making it a core part of Objective-C programming. This article explores the Foundation Framework in detail.

Types and Subtypes of Foundation Framework

Below is a summary of the key types and their respective subtypes offered by the Foundation framework:

Type	Subtype	Description
Classes	NSObject	The root class of most Objective-C classes, providing fundamental behavior and interface essentials.
Classes	NSNumber	Represents numbers for primitive types like int, float, double, and bool.
Classes	NSString	Handles Unicode strings with methods for creating, modifying, comparing, and searching strings.
Classes	NSArray	Creates and manages ordered collections of objects.
Classes	NSDictionary	Represents unordered key-value pairs, allowing access and modification of dictionary entries.
Classes	NSSet	Provides an unordered collection of unique objects with access and iteration methods.
Classes	NSData	Represents a sequence of bytes, with utilities for creating and manipulating data.
Classes	NSDate	Represents a point in time with methods for creating and manipulating dates.
Classes	NSTimer	Represents a timer that triggers at specific intervals.
Classes	NSThread	Manages threads of execution for multitasking.
Classes	NSFileHandle	Handles files or sockets for reading and writing data.
Classes	NSFileManager	Provides file system operations like creation, movement, and deletion of files and directories.
Classes	NSUserDefaults	Manages user preferences and settings.
Classes	NSNotification	Handles broadcasting messages to interested observers.
Classes	NSNotificationCenter	Manages the notification system, enabling observer registration and communication.
Protocols	NSCopying	Enables objects to provide copy functionality by implementing a required method.
Protocols	NSCoding	Supports encoding and decoding objects for archiving and unarchiving purposes.
Protocols	NSLocking	Provides locking and unlocking mechanisms for thread synchronization.
Protocols	NSFastEnumeration	Allows efficient enumeration over collections.
Categories	NSString+NSPathUtilities	Adds methods to NSString for file path manipulation.
Categories	NSArray+NSPredicate	Adds methods to filter and sort arrays using predicates.
Categories	NSObject+NSKeyValueCoding	Adds methods for property access using key-value coding.
Functions	NSLog	Prints formatted messages to the console for debugging.
Functions	NSMakeRange	Creates a structure representing a range of values.
Functions	NSClassFromString	Returns a Class object corresponding to a string name.
Functions	NSSelectorFromString	Returns a selector (SEL) object corresponding to a string.
Functions	NSHomeDirectory	Returns the path to the current user’s home directory.

Syntax and Keywords in Foundation Framework

Syntax/Keyword	Description
#import <Foundation/Foundation.h>	Imports the Foundation framework header file.
@interface ClassName : SuperClassName <ProtocolName>	Declares a class with a superclass and adopted protocols.
@end	Marks the end of an interface or implementation block.
@implementation ClassName	Defines the implementation of a class.
@property (attributes) type name	Declares a property with specified attributes.
self	Refers to the current instance of a class.
super	Refers to the superclass of the current object.
nil	Represents a null object pointer.
YES	Represents a Boolean true value.
NO	Represents a Boolean false value.

Example 1: NSNumber Class

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSNumber *intNumber = @50;
        NSNumber *floatNumber = @4.56;
        NSNumber *boolNumber = @YES;

        // Comparing NSNumber objects
        if ([intNumber compare:floatNumber] == NSOrderedAscending) {
            NSLog(@"%@ is less than %@", intNumber, floatNumber);
        } else {
            NSLog(@"%@ is greater than or equal to %@", intNumber, floatNumber);
        }

        // Conversion to different types
        int intValue = [intNumber intValue];
        float floatValue = [floatNumber floatValue];
        BOOL boolValue = [boolNumber boolValue];

        NSLog(@"Converted values - int: %d, float: %.2f, bool: %d", intValue, floatValue, boolValue);
    }
    return 0;
}

Output:

50 is less than 4.56
Converted values - int: 50, float: 4.56, bool: 1

Example 2: NSString Class

#import <Foundation/Foundation.h>

int main(int argc, const char *argv[]) {
    @autoreleasepool {
        NSString *string1 = @"Foundation Framework";
        NSString *string2 = @"Objective-C Programming";

        // String Comparison
        if ([string1 isEqualToString:string2]) {
            NSLog(@"Both strings are equal.");
        } else {
            NSLog(@"Strings are not equal.");
        }

        // Conversion to uppercase
        NSString *uppercaseString = [string1 uppercaseString];
        NSLog(@"Uppercase: %@", uppercaseString);
    }
    return 0;
}

Output:

Strings are not equal.
Uppercase: FOUNDATION FRAMEWORK

Example 3: NSArray Class

#import <Foundation/Foundation.h>

int main(int argc, const char *argv[]) {
    @autoreleasepool {
        NSArray *fruits = @[@"Apple", @"Banana", @"Cherry"];
        NSArray *vegetables = @[@"Carrot", @"Spinach"];

        // Accessing elements
        NSLog(@"First fruit: %@", [fruits firstObject]);

        // Merging arrays
        NSArray *combinedArray = [fruits arrayByAddingObjectsFromArray:vegetables];
        NSLog(@"Combined array: %@", combinedArray);
    }
    return 0;
}

Output:

First fruit: Apple
Combined array: (
    Apple,
    Banana,
    Cherry,
    Carrot,
    Spinach
)