Foundation框架基础 NSData-数据

#import<Foundation/Foundation.h>

/*
 概念： IOS中二进制文件使用NSData保存

 音频、视频文件必须使用NSData来保存

 */
intmain(intargc, const char * argv[]) {
    @autoreleasepool {
//      读取文件
        NSMutableData *dataM = [NSMutableDatadata];
        NSData *d1 = [@"today is "dataUsingEncoding:NSUTF8StringEncoding];

       NSData *d2 = [@"a good day "dataUsingEncoding:NSUTF8StringEncoding];

//      添加数据
        [dataM appendData:d1];

        [dataMappendData:d2];

//      把NSData转换为NSString
        NSString *string  =  [[NSStringalloc] initWithData:dataMencoding:NSUTF8StringEncoding];
        NSLog(@"%@",string);
    }
    return 0;
}

voidtestNSData()
{
    //      读取文件
    NSData *data = [NSDatadataWithContentsOfFile:@"/Users/apple/Desktop/Snip20141111_21.png"];

   NSLog(@"%zd",data.length);

    //      数据写入文件
    BOOL isSuccess = [datawriteToFile:@"/Users/apple/Desktop/dir/test.png"atomically:YES];
    if (isSuccess) {
        NSLog(@"写入成功！");
    }
}