increment in array

Question

What is the output of this code in c?

int main(){
static int a[][2][3]={0,1,2,3,4,5,6,7,8,9,10,11,12};
int i=-1;
int d;
d=a[i++][++i][++i]; printf("%d",d); return 0;
}

 

how did 2 come as the answer? please explain,thanks.

Comments

d=a[i++][++i][++i];

with in the next sequence point, variable updated more than once ===> undefined behavior in C