Why Xcode doesn't recognize a class I created? - ios

Question

I am new to programming and is in the process of learning objective-c from Big Nerd Ranch. Using x-code, I am trying to create a class. Upon creating the class, X-Code is not recognizing it in main file. I created a new project, then created a new file ensuring the correct target was selected. When I try to type triangle, it says "Use of undeclared identifier." What am I doing wrong? Please help.
This is my header file.
#import <Foundation/Foundation.h>
#interface Triangle : NSObject
{
float lengthSideA;
float lengthSideB;
float lengthSideC;
}
#property float lengthSideA;
#property float lengthSideB;
#property float lengthSideC;
-(float) area;
-(float) perimeter;
-(float) hypothenuse;
#end
And this is my implementation file.
#import "Triangle.h"
#implementation Triangle
#synthesize lengthSideA, lengthSideC, lengthSideB;
-(float) perimeter
{
float a = [self lengthSideA];
float b = [self lengthSideB];
float c = [self lengthSideC];
return a + b + c;
}
-(float) area
{
float a = [self lengthSideA];
float b = [self lengthSideB];
return b * a / 2;
}
-(float) hypothenuse
{
float a = [self lengthSideA];
float b = [self lengthSideB];
return sqrt(a * a + b * b);
}
#end

Answer 1

Add #import "Triangle.h" in the class where you are using your Triangle class. You have to import any external class before you can use it.

Answer 2

First of all check if the file is imported. If it is imported, go to build settings and check if the header of the file is added to the compile sources. Also check if the file is added to the main bundle properly. I hope you selected the tick option which says add the reference of the file while adding the file. Hope it helps :)