系统学习ObjectiveC<基础>

#import <Foundation/Foundation.h>
BOOL areInstDifferent(int thing1, int thing2);
NSString *boolString(BOOL yesNO);
BOOL areInstDifferent(int thing1, int thing2)
{
    if(thing1 == thing2)
    {
        return (NO);
    }
    else
   {
        return (YES);
   }
}

NSString *boolString(BOOL yesNO)
{
    if(yesNO == NO)
    {
         return (@"NO");
    }
    else
    {
         return (@"YES");
    }
}

int main(int argc, const char * argv[])
{
     @autoreleasepool
     {
          BOOL areTheyDifferent;
          areTheyDifferent = areIntsDifferent(5, 5);
          NSLog(@"are %d and %d different? %@", 5, 5, boolString(areTheyDifferent));
          areTheyDifferent = areIntsDifferent(23, 42);
          NSLog(@"are %d and %d different? %@", 23, 42, boolString(areTheyDifferent));
     }
     return 0;
}

以上简单的代码就是对Objective-C的很好的解释，跟C语言区别不是很大，但也有不同，值得注意的就是：#import <Foundation/Foundation.h>、NSLog(@"");、BOOL的使用,要特别注意以上三个与C语言中的区别，不要掉进BOOL的陷阱中。