const int size = 16; int i;
float list[size];
...
if (i < 0 || i >= size) {
  cout << "Error: Index out of range";
} else {
  list[i] += 1.0f;
}

if ((unsigned int)i < (unsigned int)size) {
  list[i] += 1.0f;
} else {
  cout << "Error: Index out of range";
}

const int min = 100, max = 110;
...
if (i >= min && i <= max) { ...

if ((unsigned int)(i - min) <= (unsigned int)(max - min)) { ...