objective-c - 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，例如 char、long...等等，还有 nsdate、nsdictionary、frame...。我现在想打印每个类型变量的值。

Answer 1

int、float、double 等基本类型可以使用 printf、fprintf 等以与在 C 中打印相同的方式打印。如果您需要打印一个类的数据你经常可以使用NSObject的方法(NSString *)description来得到一个代表类数据的NSString物体。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:我认为在示例运行时查看输出会有所帮助...

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!"
)