Constants

Question

If we don't declare a var / char as constant why does the code still function instead of printing double the value given like in the example I've gotten below without declaring that PI is a constant the output still remains the value of PI?
int main() {
double PI = 3.14;
const double PI = 3.14;
printf("%f \n", PI);
return 0;
}

Answer 1

We get error because a variable can be declared only once .
But we can define a variable no.of times

Answer 2

is it possible that you can elastrate with a simple code program?