macOS Learning objective c on the mac

[Frankymac]

I've been reading this book and am having trouble with one of the sample codes that the author calls "bool party". I keep getting error when i try to "build and run". I've typed the code exactly as it appears in the book but i can't get it to work. Anyone familiar with this title? "learning objective c on the mac"

thank you

#import <Foundation/Foundation.h>

//returns NO if the two integers have the same
//value, YES otherwise

BOOL areIntsDifferent (int thing1, int thing2)
{
	if (thing1== thing2) {return(NO);}else {return (YES);}
}//areIntsDifferent

//given a NO value, return the human-readable
// strin "NO". Otherwise return "YES"

NSString *boolString (BOOL yesno)
{
	if (yesNo == NO) {return (@"NO");} else { return (@"YES");  [I]Here I get "yesNo undeclared"[/I]
	}

// boolstring
int main (int argc, const char *argv[])[I] here I get "nested functions are disabled use fnested functions[/I]
{
	BOOL areTheyDifferent; areTheyDifferent = areIntsDifferent (5, 5);
NSLog (@"are %d and %d different? %@", 5, 5, boolString(areTheyDifferent));

areTheyDifferent = areIntsdifferent (23, 42);  [I]Here I get "Implicit declaration of function"[/I]

NSLog (@"are %d and %d different? %@", 23, 42, boolString(areTheyDifferent));

return(0)
	;} //main  [I]Expected declaration of input"[/I]

 

[Cromulent]

If you want help with any programming problem always post the relevant code and the exact error message or no one will be able to help you. Chances are you have missed a semi-colon somewhere.

 

[Frankymac]

Thanks cromulent

I followed your advice. Could you give any advice about the code? It's very frustrating. Thanks Frank

 

[lee1210]

C, and Objective-C, are case-sensitive. yesNo is not the same variable as yesno. areIntsdifferent is a different function than areIntsDifferent.

Also, you missed a closing } in this code:

NSString *boolString (BOOL yesno)
{
if (yesNo == NO) {return (@"NO");} else { return (@"YES"); Here I get "yesNo undeclared"
}

Change this to:

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

or

NSString *boolString (BOOL yesNo) {
  return yesNo==YES?@"YES":@"NO";
}

This should fix the nested function business. It things you're declaring main inside of boolString.

-Lee

 

[Frankymac]

Thanks Lee

I'll give it a try.

Frank

 

[dukeofism]

I'll give it a try.

Frank

Just a general tip: (this may be because you didn't post your code in the code brackets) Your code is shown on this forums as all starting at the beginning of each line with no indentation. Including indentation for code that falls under a function or within a loop/ if-selector makes your code much more readable. Readability is something that you want your code to have because an increase in code readability makes it easier for you and other to read which makes for easier code to debug. Good luck with learning Objective-C!

 

[Frankymac]

Thanks for the advice dukeofism.

Thanks.

 

[MorphingDragon]

I've been reading this book and am having trouble with one of the sample codes that the author calls "bool party". I keep getting error when i try to "build and run". I've typed the code exactly as it appears in the book but i can't get it to work. Anyone familiar with this title? "learning objective c on the mac"

thank you

#import <Foundation/Foundation.h>

//returns NO if the two integers have the same
//value, YES otherwise

BOOL areIntsDifferent (int thing1, int thing2)
{
	if (thing1== thing2) {return(NO);}else {return (YES);}
}//areIntsDifferent

//given a NO value, return the human-readable
// strin "NO". Otherwise return "YES"

NSString *boolString (BOOL yesno)
{
	if (yesNo == NO) {return (@"NO");} else { return (@"YES");  [I]Here I get "yesNo undeclared"[/I]
	}

// boolstring
int main (int argc, const char *argv[])[I] here I get "nested functions are disabled use fnested functions[/I]
{
	BOOL areTheyDifferent; areTheyDifferent = areIntsDifferent (5, 5);
NSLog (@"are %d and %d different? %@", 5, 5, boolString(areTheyDifferent));

areTheyDifferent = areIntsdifferent (23, 42);  [I]Here I get "Implicit declaration of function"[/I]

NSLog (@"are %d and %d different? %@", 23, 42, boolString(areTheyDifferent));

return(0)
	;} //main  [I]Expected declaration of input"[/I]

Please learn some code layout, helps a bunch when other try read code. Plus it can avoid syntax errors.

 

[naituw]

another way

I wrote this

#import <Foundation/Foundation.h>
NSString *areintsdifferent (int a,int b)
{int c;
	c=a-b;
if (c == 0) {
	return (@"NO");
}
else {
	return (@"YES");
}
}

int main (int argc, const char *argv[])
{int x,y;
	scanf("%d%d",&x,&y);
	NSLog(@"%@",areintsdifferent(x, y));
}