大部分是模仿
////  main.m//  OC-API-不可變字符串////  Created by wangtouwang on 15/3/25.//  Copyright (c) 2015年 wangtouwang. All rights reserved.//#import <Foundation/Foundation.h>//初始化void testInit(){    //創建C 字符串對象    char str0 ="C String";    //創建字符串對象 無需釋放內存    NSString *str1 = @"MAIKE";    //創建字符串對象 需要釋放內存    NSString *str2 = [[NSString alloc] initWithString : @"JACK" ];    NSString *str3 = [[NSString alloc] initWithFormat:@"LUCY %i",12];    NSString *str4 = [[NSString alloc] initWithUTF8String:"C String"];        //以上方法都有對于的靜態方法,也無需釋放內存    str2 = [NSString stringWithString:@"STATIC JACK"];    str3 = [NSString stringWithFormat:@"STATIC LUCY %i",12];    str4 = [NSString stringWithUTF8String:"C String"];}int main(int argc, const char * argv[]) {    @autoreleasepool {      //轉換成大寫        NSLog(@"zhangjianhua 轉換成 大寫 %@",[@"zhangjianhua" uppercaseString]);     //轉換成小寫        NSLog(@"ZHANGJIANHUA 轉換成 小寫 %@",[@"ZHANGJIANHUA" lowercaseString]);     //首字母大寫        NSLog(@"zhangjianhua 轉換成 小寫 %@",[@"zhangjianhua" capitalizedString]);      //比較字符串內容        NSLog(@" ABC isEqualToString Abc to result= %i",[@"ABC" isEqualToString:@"Abc"]);        //比較字符串內容 忽略大小寫        NSComparisonResult result2= [@"abc" compare:@"aBc"];//如果是[@"abc" caseInsensitiveCompare:@"aBc"]則忽略大小寫比較        if(result2==NSOrderedAscending){            NSLog(@"left<right.");        }else if(result2==NSOrderedDescending){            NSLog(@"left>right.");        }else if(result2==NSOrderedSame){            NSLog(@"left=right.");        }        //查詢指定字符串在前綴什么位置        NSLog(@" ABCDEFJ BY CD in location %i",[@"ABCDEFJ" hasprefix:@"CD"]);        //查詢指定字符串在后綴什么位置        NSLog(@" ABCDEFJ BY FJ in location %i",[@"ABCDEFJ" hasSuffix:@"F"]);        //查詢指定字符串在什么位置和長度        NSLog(@" ABCDEFJ BY CD in location %@", NSStringFromRange([@"ABCDEFJ" rangeOfString:@"CD"]));        //截取指定字符串位置 根據CGRange對象        NSLog(@"java Subetring TO Result  %@",[@"ABCDEFG" substringWithRange:NSMakeRange(2, 2)]);        //截取指定字符串對象 根據下標 從0到了該位置就停止        NSLog(@"SubString String By Index %@",[@"ABCDEFG" substringToIndex:2]);        //截取指定字符串對象 根據下標 從位置到結尾停止        NSLog(@"SubString String By Index %@",[@"ABCDEFG" substringFromIndex:2]);                //字符串分割        NSString *str9 = @"MY NAME IS WP,AGE=28";        NSArray *array = [str9 componentsSeparatedByString:@" "];        NSLog(@"%@",array);                //內型轉換        //轉換成int        NSLog(@"%i",[@"13" intValue]);        //轉換成C語音字符串        const char *s=[@"abc" UTF8String];//轉換為C語言字符串        NSLog(@"%s",s);               NSLog(@"%c",[@"abc" characterAtIndex:0]);//取出制定位置的字符            }    return 0;}