OC9_字符串的内存管理

//
//  main.m
//  OC9_字符串的内存管理
//
//  Created by zhangxueming on 15/6/18.
//  Copyright (c) 2015年 zhangxueming. All rights reserved.
//

#import <Foundation/Foundation.h>

//字符串内存管理, retainCount的值可以不参考, 只需要遵守内存管理法则就行
int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSString *str1 = @"hello world";
        NSLog(@"str1 retainCount = %li", str1.retainCount);
        NSString *str2 = [NSString stringWithString:str1];
        NSLog(@"str2 retainCount = %li", str2.retainCount);
        NSString *str3 = [[NSString alloc] initWithString:str1];
        NSLog(@"str3 retainCount = %li",str3.retainCount);

        NSLog(@"str1 = %p str2 = %p str3 = %p", str1, str2, str3);
        [str3 release];

        NSString *str4 = [str3 retain];
        NSLog(@"str4 retainCount = %li", str4.retainCount);
        [str4 release];

        NSString *str5 = [str4 copy];
        NSLog(@"str5 retainCount = %li", str5.retainCount);
        NSLog(@"str5 = %p str4 = %p", str5, str4);
        [str5 release];

        NSMutableString *mulStr1 = [[NSMutableString alloc] initWithString:str5];
        NSLog(@"mulStr1 retainCount = %li", mulStr1.retainCount);
        NSLog(@"mulStr1 = %p str5 = %p", mulStr1, str5);

        NSMutableString *mulStr2 = [mulStr1 retain];
        NSLog(@"mulStr2 retainCount = %li", mulStr2.retainCount);

        NSString *str6 = [[NSString alloc] initWithString:mulStr1];
        NSLog(@"str6 retainCount = %li", str6.retainCount);

        NSString *str7 = [[NSString alloc] init];//@""
        NSLog(@"str7 retainCount = %li", str7.retainCount);

        NSLog(@"str6 = %p str7 = %p", str6, str7);

        NSString *str8 = [str7 stringByAppendingString:@"qian feng"];

        NSLog(@"str8 retainCount = %li", str8.retainCount);
        NSLog(@"str8 = %p", str8);

        [str6 release];
        [str7 release];
        [mulStr1 release];
        [mulStr2 release];
    }
    return 0;
}