2016-08-31 21:11:54.883 mylearn[596:34753] 10
2016-08-31 21:11:54.884 mylearn[596:34753] 12
2016-08-31 21:11:54.884 mylearn[596:34753] 0xa
2016-08-31 21:11:54.885 mylearn[596:34753] 3.141593
2016-08-31 21:11:54.885 mylearn[596:34753] 3.141593e+00
2016-08-31 21:11:54.885 mylearn[596:34753] 3.14159

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // insert code here...
        NSLog(@"%i",10);
        NSLog(@"%o",10);
        NSLog(@"%#x",10);
        NSLog(@"%f",3.1415926);
        NSLog(@"%e",3.1415926);
        NSLog(@"%g",3.1415926);
    }
    return 0;
}

i表示10进制

o表示8进制

#x表示带有ox前缀符的16进制

f表示符点数

e表示科学计数法

g表示以最短方式输出浮点数