我们如何在Objective-C中打印不同类型的数据类型？

Question

我想打印所有类型的值,如char,long ...等等,还有nsdate,nsdictionary,frame ....我现在要打印每个类型变量的值.

Answer 1

原语类型,如整数,浮点,双,等可以在它们被打印在C相同的方式进行打印,使用printf,fprintf等等.如果需要打印的一类经常可以使用数据NSObject的方法(NSString *)description,以得到一个NSString代表对象的数据.这是一个例子......

#import <Foundation/Foundation.h>

int main (int argc, const char * argv[]) {
    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    NSString *string = [NSString stringWithFormat:@"Hello World!"];
    NSDate *date = [NSDate dateWithTimeIntervalSinceNow:0];
    NSArray *array = [NSArray arrayWithObject:@"Hello There!"];

    char *c_string = "Familiar ol' c string!";
    int number = 3;

    printf("C String: %s\n",c_string);
    printf("Int number: %u\n", number);
    //In 10.5+ do not use [NSString cString] as it has been deprecated
    printf("NSString: %s\n", [string UTF8String]);
    printf("NSDate: %s\n", [date.description UTF8String]);
    printf("NSArray: %s\n", [array.description UTF8String]);

    //If you are using this information for debugging, it's often useful to pass the object to NSLOG()

    NSLog(@"NSArray *array = \n%@", array);

    [pool drain];
    return 0;
}

编辑:我认为在运行示例时查看输出会很有帮助...

C String: Familiar ol' c string!
Int number: 3
NSString: Hello World!
NSDate: 2010-03-12 01:52:31 -0600
NSArray: (
    "Hello There!"
)
2010-03-12 01:52:31.385 printfTest[2828:a0f] NSArray *array = 
(
    "Hello There!"
)