强转基本数据类型

union A{
        int a;
        char b[4];
    }a;
    a.a=1;
    if (a.b[0] == 0)
    {
        
        NSLog(@"big");
    } else {
        //小端
        NSLog(@"little");
    }

long long l = 0x1234567887654321;
   int i = l >>32 & 0xffffffff;
   int j = (int)l;
   int16_t t = (int16_t)l;
   NSLog(@"l = %llx i = %x j = %x t = %x" , l ,i ,j , t);