Assuming you use the correct syntax: char array[10] = {'1','2','3','4','5','6','7','8','9'};
There is a relationship between the index of the array element and the value you need:
k=3;
chr=array[k];
ival=k+1;
Now chr would be '4' and ival would be 4. There is another trick that I've used from time to time:
ival = (int)chr - (int)'0';
It assumes ascii or some other character set that behaves this way. But I have used it anyway.