Object-c------foudation中的NSString

main.m

//
// main.m
// 02-NSString
//
// Created by apple on 13-8-12.
// Copyright (c) 2013年 itcast. All rights reserved.
//

#import <Foundation/Foundation.h>
/* NSString : 不可变字符串 NSMutableString : 可变字符串 */


int main()
{

    NSMutableString *s1 = [NSMutableString stringWithFormat:@"my age is 10"];
    // 拼接内容到s1的后面
    [s1 appendString:@" 11 12"];

    // 获取is的范围
    NSRange range = [s1 rangeOfString:@"is"];
    [s1 deleteCharactersInRange:range];

    NSString *s2 = [NSString stringWithFormat:@"age is 10"];

    NSString *s3 = [s2 stringByAppendingString:@" 11 12"];


    NSLog(@"s1=%@, s2=%@", s1, s2);

    return 0;
}

void stringExport()
{
    // 字符串的导出
    [@"Jack\nJack" writeToFile:@"/Users/apple/Desktop/my.txt" atomically:YES encoding:NSUTF8StringEncoding error:nil];


    NSString *str = @"4234234";
    NSURL *url = [NSURL fileURLWithPath:@"/Users/apple/Desktop/my2.txt"];
    [str writeToURL:url atomically:YES encoding:NSUTF8StringEncoding error:nil];
}

void stringCreate()
{
    /* 1.字符串的创建 */
    NSString *s1 = @"jack";

    //NSString *s2 = [[NSString alloc] initWithString:@"jack"];

    NSString *s3 = [[NSString alloc] initWithFormat:@"age is %d", 10];

    // C字符串 --> OC字符串
    NSString *s4 = [[NSString alloc] initWithUTF8String:"jack"];
    // OC字符串 --> C字符串
    const char *cs = [s4 UTF8String];

    // NSUTF8StringEncoding 用到中文就可以用这种编码
    NSString *s5 = [[NSString alloc] initWithContentsOfFile:@"/Users/apple/Desktop/1.txt" encoding:NSUTF8StringEncoding error:nil];


    // URL : 资源路径
    // 协议头://路径
    // file://
    // ftp://
    // http://weibo.com/a.png


    // http://www.baidu.com

    // NSURL *url = [[NSURL alloc] initWithString:@"file:///Users/apple/Desktop/1.txt"];
    NSURL *url = [NSURL fileURLWithPath:@"/Users/apple/Desktop/1.txt"];

    NSString *s6 = [[NSString alloc] initWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];
    NSLog(@"s6=\n%@", s6);


    /* 一般都会有一个类方法跟对象方法配对 [NSURL URLWithString:<#(NSString *)#>]; [NSString stringWithFormat:@""]; [NSString stringWithContentsOfFile:<#(NSString *)#> encoding:<#(NSStringEncoding)#> error:<#(NSError *__autoreleasing *)#>]; */

}