How to covert unsigned char[4] to unsigned integer?

Question

#include <stdio.h>
int main()
{
  char val=250;
  int ans;
  ans= val+ !val + ~val + ++val;
  printf("%d",ans);
  return 0;
}

Answer 1

I would like to explain by using following sample piece of code:
char[4] ch = {'1', '2', '3', '4'};
int i = 0;
n = 4;
for (i = 0; i < n ; i++)
{
i += (ch[i] - '0') * pow(10, n-i-1);
}

Now, i has converted integer value of i