Definition of global variables using a non constant initializer

Question

#include 

int i=10;
int j=i;
int main()
{
    printf(\"%d\",j);
}

I get an error stating that initialization element is not a const

Answer 1

What is the reason behind this?

C(unlike C++) does not allow initialization of global values with non constant values.

C99 Standard: Section 6.7.8:

All the expressions in an initializer for an object that has static storage duration shall be constant expressions or string literals.