Objective C Tutorial - Objective C NSNumber

The following table lists the methods from NSNumber.

+ (NSNumber *)numberWithBool:(BOOL)value
Creates and returns an NSNumber object for a BOOL value.
+ (NSNumber *)numberWithChar:(char)value
Creates and returns an NSNumber object from a signed char value.
+ (NSNumber *)numberWithDouble:(double)value
Creates and returns an NSNumber object from a double value.
+ (NSNumber *)numberWithFloat:(float)value
Creates and returns an NSNumber object from a float value.
+ (NSNumber *)numberWithInt:(int)value
Creates and returns an NSNumber object from a signed int.
+ (NSNumber *)numberWithInteger:(NSInteger)value
Creates and returns an NSNumber object from an NSInteger.
- (BOOL)boolValue
Returns the value as a BOOL.
- (char)charValue
Returns the value as a char.
- (double)doubleValue
Returns the value as a double.
- (float)floatValue
Returns the value as a float.
- (NSInteger)integerValue
Returns the value as an NSInteger.
- (int)intValue
Returns the value as an int.
- (NSString *)stringValue
Returns the value as a human-readable string.

#import <Foundation/Foundation.h>
 
int main ()
{
  NSNumber *myNumber;
    myNumber = [NSNumber numberWithFloat:3.47];
    NSLog (@"The value in NSNumber = %@", myNumber);  
 
   return 0;
}

The code above generates the following result.

Example

The following code shows how to use NSNumber to multiply two numbers and returns the product.

#import <Foundation/Foundation.h>

@interface SampleClass:NSObject

- (NSNumber *)multiplyA:(NSNumber *)a withB:(NSNumber *)b;

@end

@implementation SampleClass

- (NSNumber *)multiplyA:(NSNumber *)a withB:(NSNumber *)b
{
   float number1 = [a floatValue];
   float number2 = [b floatValue];
   float product = number1 * number2;
   NSNumber *result = [NSNumber numberWithFloat:product];
   return result;
}

@end

int main()
{
   NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

   SampleClass *sampleClass = [[SampleClass alloc]init];
   NSNumber *a = [NSNumber numberWithFloat:10.5];
   NSNumber *b = [NSNumber numberWithFloat:10.0];   
   NSNumber *result = [sampleClass multiplyA:a withB:b];
   NSString *resultString = [result stringValue];
   NSLog(@"The product is %@",resultString);

   [pool drain];
   return 0;
}

Convert Float NSNumber to String


#import <Foundation/Foundation.h>

int main (int argc, const char * argv[])
{

        
        float fNumber = 12;
        
        NSString *floatToString = [NSString stringWithFormat:@"%f", fNumber];
        
        NSLog(@"floatToString = %@", floatToString);
        
        NSNumber *number = [NSNumber numberWithFloat:30];
        
        NSString *numberToString = [number stringValue];
        
        NSLog(@"numberToString = %@", numberToString);
        
    return 0;
}

The code above generates the following result.

Convert String to Number

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[])
{

        
        NSString *aFloatValue = @"12.50";
        
        float f = [aFloatValue floatValue];
    
        float result = f * 2 + 45;
        
        NSLog(@"f = %f and result = %f", f, result);
        
        NSNumber *aFloatNumber = [NSNumber numberWithFloat:[aFloatValue floatValue]];
        
        NSLog(@"aFloatNumber = %@", aFloatNumber);
        
    return 0;
}

The code above generates the following result.

Format a Number

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[])
{

        
        NSNumber *numberToFormat = [NSNumber numberWithFloat:9.99];
        
        NSLog(@"numberToFormat = %@", numberToFormat);
        
        NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];
        
        numberFormatter.numberStyle = NSNumberFormatterCurrencyStyle;
        
        NSLog(@"Formatted for currency: %@", [numberFormatter stringFromNumber:numberToFormat]);
        
        numberFormatter.numberStyle = NSNumberFormatterSpellOutStyle;
        
        NSLog(@"Formatted for spelling out: %@", [numberFormatter stringFromNumber:numberToFormat]);
        
    return 0;
}