每日一练: OC中的NSString及常用的几个方法

#import <Foundation/Foundation.h>
int main(int argc, const char * argv[]) {    @autoreleasepool {        // insert code here...
        //直接赋值        NSString *myCountry = @"My Country is China";        NSLog(@"The sentence is %@ \n", myCountry);
        //赋值使用特定的格式        NSDate *now = [NSDate date];        NSString *theDateNow = [NSString stringWithFormat:@"The time is %@", now];        NSLog(@"Now the string is %@", theDateNow);                //NSString 一些常用方法                NSString *orignalString = @"This is an Apple";                //Check the length                NSUInteger stringlen = [orignalString length];        NSLog(@"The String length is %lu \n", stringlen);                //Change to Upper Cases        NSString *upperString = [orignalString uppercaseString];        NSLog(@"Now the String is: %@ \n", upperString);                NSString *secondString = @"This is an apple";                if ([orignalString isEqualToString:secondString]) {            NSLog(@"The two Strings are same");        } else {            NSLog(@"The two Strings are not same");        }                NSString *string = @"Hi,boy.";        NSLog(@"My string is %@ \n", string);        NSString *thirdString = [[NSString alloc] initWithString:string];        NSLog(@"The third String is %@ \n", thirdString);                //(unichar)characterAtIndex:(NSUInteger)index;        unsigned short achar = [thirdString characterAtIndex:2];        NSLog(@"The second char is %hu \n",achar);                //to check the method-hasPrefix        if([string hasPrefix:@"Him"]){            NSLog(@"Yes, it has Him");        }else{            NSLog(@"No, it does not have a him");        }                //convert the string to int                NSString *stringWithNum = @"234";        int stringNum = [stringWithNum intValue];        NSLog(@"The value for stringNum is %d \n", stringNum);                //string append new string                NSString *forthString = [thirdString stringByAppendingString:@" I Love OC"];        NSLog(@"The forth string is %@", forthString);    }        return 0;}

Result:
2018-03-10 23:07:18.558085+0800 TOCObjectivea[56935:13868635] The sentence is My Country is China2018-03-10 23:07:18.561513+0800 TOCObjectivea[56935:13868635] Now the string is The time is 2018-03-10 15:07:18 +00002018-03-10 23:07:18.561571+0800 TOCObjectivea[56935:13868635] The String length is 162018-03-10 23:07:18.561678+0800 TOCObjectivea[56935:13868635] Now the String is: THIS IS AN APPLE2018-03-10 23:07:18.561709+0800 TOCObjectivea[56935:13868635] The two Strings are not same2018-03-10 23:07:18.561727+0800 TOCObjectivea[56935:13868635] My string is Hi,boy.2018-03-10 23:07:18.561748+0800 TOCObjectivea[56935:13868635] The third String is Hi,boy.2018-03-10 23:07:18.561764+0800 TOCObjectivea[56935:13868635] The second char is 442018-03-10 23:07:18.561778+0800 TOCObjectivea[56935:13868635] No, it does not have a him2018-03-10 23:07:18.561840+0800 TOCObjectivea[56935:13868635] The value for stringNum is 2342018-03-10 23:07:18.561985+0800 TOCObjectivea[56935:13868635] The forth string is Hi,boy. I Love OCProgram ended with exit code: 0