Constant or Final Variables in C Language

C Programming Language supports to declare a variable for which value can not be changed in run-time. Hence, it should be initialized at the time of declaration, it can not be initialized later.

#include <stdio.h> int main(void) { const int max = 10; printf("%d\n", max); //max = 5; can not be changed.... printf("%d\n", max); return 0; }

If the variable is not initialized at the time of declaration, 0 is assigned to it as default value for integer, floating point number as well as character.

#include <stdio.h> int main(void) { const int x; const float f; const char c; printf("%d\n", x); printf("%f\n", f); printf("%d\n", c); //x = 5; can not be changed.... //f = 2.0; can not be changed.... //c = 'A'; can not be changed.... return 0; }

Hence, if you need a variable, which should not be changed during execution, you can declare it as constant. For example, the variable PI=3.142 can be declared as constant.

Happy Exploring!