C Arrays Questions

#include<stdio.h>
enum power{
    Dalai,
    Vladimir=3,
    Barack,
    Hillary
};
void main(){
    float leader[Dalai+Hillary]={1.f,2.f,3.f,4.f,5.f};
    enum power p=Barack;
    printf("%0.f",leader[p>>1+1]);
}

Output:2

Size of an array can be enum constantan.
Value of enum constant Barack will equal to Vladimir + 1 = 3 +1 = 4
So, value of enum variable p  = 4
leader[p >> 1 +1]
= leader[4 >> 1+1]
=leader[4 >> 2]   //+ operator enjoy higher precedence than >> operator.
=leader[1]  //4>>2 = (4 / (2^2) = 4/4 = 1
=2

#include<stdio.h>
void main(){
    int const SIZE=5;
    int expr;
    double value[SIZE]={2.0,4.0,6.0,8.0,10.0};
    expr=1|2|3|4;
    printf("%f",value[expr]);
}

Size of any array in c cannot be constantan variable.