Knowledge Walls
Venkatesan
Hyderabad, Andhra Pradesh, India
Passcode:
Introduction [cont'd]
Input Output Functions [cont'd]
Structures and Unions [cont'd]
# Preprocessor [cont'd]
#undef in # Preprocessor of Programming in C
2224 Views
#undef 
#undef is a preprocessor directive statement. It is used to undefined a defined constants.
Syntax 
#undef defined_variable;
Program
	#include
	#ifdef PI
	#undef PI
	#define PI 3.14
	#else
	#define PI 3.14
	#endif
	void main(){
	   printf("PI = %5.2f",PI);
	}
Output 
PI = 3.14
Previous Topics
Previous lessons of current book.
# Preprocessor of Programming in C
# Preprocessor of Programming in C
# Preprocessor of Programming in C
# Preprocessor of Programming in C
# Preprocessor of Programming in C
Best Lessons of "Programming in C"
Top lessons which are viewed more times.
Structures and Unions of Programming in C
Input Output Functions of Programming in C
Structures and Unions of Programming in C
  Copyright © 2014 Knowledge walls, All rights reserved
KnowledgeWalls
keep your tutorials and learnings with KnowledgeWalls. Don't lose your learnings hereafter. Save and revise it whenever required.
Click here for more details