Define constant variables in C++ header
Hello readers! In this tutorial, we are going to learn how we can define constant variables in the C++ header file. In C++ constant variables are defined as the types of variables whose value can’t be changed once they are defined, they remain fixed all throughout the program.
In C++ a variable can be declared constant by 2 ways:
- Using #define keyword method
Syntax:- #define identifier_name value
Example- #define var3 290
- By using const keyword method
Syntax:- const datatype identifier_name = value
Example- const int var8 = 300
C++ Code: constant variables in C++ header
Refer to the code below to see both the ways :
Refer to the comments in the code for better understanding
#include <iostream> #define var1 89 const int var2=340; //using const keyword method int main() { std::cout<<var1<<" "<<var2; //using std::cout for output }
Output:
89 340
Explanation of the code:
Using #define declare a constant variable with constant value. Now using const keyword declare another constant variable. Declare the main function . The output values of both the variables will be printed using std::cout.
That’s all for the tutorial. Hope you liked it!
Happy learning!
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