Constant variable is a variable whose value cannot be changed during the execution of the program. And if we try to change the value, an error will get generated.
const datatype variable=value;
A constant is declared using the keyword “const”.
const int a=10; valid
A constant has to be initialized at the time of declaration.
(i) const int a=10; //valid
(ii) const int a; //invalid
Question:Which of the following is better and why?
(a). float pi=3.1415;
(b). const float pi=3.1415;
(b) is better as it declares pi as constant. If we try to change the value it will generate an error.