可变长度字符串

// main.m

// 08-可变长度字符串

// Created by apple on 14-3-20.

#import <Foundation/Foundation.h>

int main(int argc, const char * argv[])

{

@autoreleasepool {

NSString * str = @"abc";

NSString * str2 = [str stringByAppendingString:@"bbc"];

NSLog(@"str2 %@ str %@",str2,str);

str = @"abcbbc";

//1.创建可变字符串

//NSMutableString 继承自 NSString

//NSMutableString 用油NSString所有的属性以及方法

// NSMutableString * muStr = [[NSMutableString alloc] init];

NSMutableString * muStr = [[NSMutableString alloc] initWithCapacity:0];

//是初始化字符串内容

[muStr setString:@"www"];

NSLog(@"mustr %p",muStr);

//动态的给字符串末尾追加新值

[muStr appendString:@".cn"];

//在指定的索引位置,插入字符串

[muStr insertString:@".itcast" atIndex:3];

//删除指定范围的字符串

//你要删除的长度,一定不能够超出字符串的的长度,导致异常Range or index out of bounds

NSRange range = {3,7};

// [muStr deleteCharactersInRange:range];

[muStr replaceCharactersInRange:range withString:@"传智播客"];

NSLog(@"muStr %@",muStr);

}

return 0;

}