NSLog datatype formatting option in Objective-C

NSLog in Objective-C is function call that is useful during debugging of a program. A typical NSLog example is

NSLog(@” How to use NSLog”);

The above statement prints the message ” How to use NSLog ” in console window. If you want to print the value of Objective-C variable or data type then you need to pass the relevant formatting parameter depending on data type. We have already seen different datatype and qualifiers in Objective-C, below is example Objective-C program with NSLog formatting option for each datatypes.

#import <Foundation/Foundation.h>

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

{

int i = 5;

float f = 5.3;

double d = 66.76;

long int li = 22;

short int si = 12;

char c = ‘W’;

signed int sint = 34;

unsigned int uint = –23;

int o = 024;

int h = 0xAD;

long long ll = 45;

long double lf = 34.5;

unsigned long long ull = 12;

NSString *msg = @”NSLog Message”;

@autoreleasepool {

NSLog(@” print int %d”, i);

NSLog(@” print float %f”, f); // use %e for exponential

NSLog(@” print double %f”, d); // use %e for exponential

NSLog(@” print long int %li”, li);

NSLog(@” print short int %i”, si);

NSLog(@” print char %c”, c);

NSLog(@” print signed int %i”, sint);

NSLog(@” print unsigned int %u”, uint);

NSLog(@” print octal %o”, o);

NSLog(@” print hexadecimal %X”, h);

NSLog(@” print long long %lld”, ll);

NSLog(@” print long double %Lf”, lf);

NSLog(@” print unsigned long long %llu”, ull);

NSLog(@” print Object %@”, msg);

}

return 0;

}

The console output of the above Objective-C program is shown below

2013-03-04 07:25:10.187 NSLog Example[362:303] print int 5

2013-03-04 07:25:10.189 NSLog Example[362:303] print float 5.300000

2013-03-04 07:25:10.189 NSLog Example[362:303] print double 66.760000

2013-03-04 07:25:10.190 NSLog Example[362:303] print long int 22

2013-03-04 07:25:10.190 NSLog Example[362:303] print short int 12

2013-03-04 07:25:10.190 NSLog Example[362:303] print char W

2013-03-04 07:25:10.191 NSLog Example[362:303] print signed int 34

2013-03-04 07:25:10.191 NSLog Example[362:303] print unsigned int 4294967273

2013-03-04 07:25:10.192 NSLog Example[362:303] print octal 24

2013-03-04 07:25:10.192 NSLog Example[362:303] print hexadecimal AD

2013-03-04 07:25:10.193 NSLog Example[362:303] print long long 45

2013-03-04 07:25:10.193 NSLog Example[362:303] print long double 34.500000

2013-03-04 07:25:10.194 NSLog Example[362:303] print unsigned long long 12

2013-03-04 07:25:10.194 NSLog Example[362:303] print Object NSLog Message

int %d or %i

float %f or %e

double %f or %e

long int %li

short int %i

char %c

signed int %i

unsigned int %u

octal %o

hexa %X

long long %lld

long double %Lf

unsigned long long %llu

object %@