Hey people. The following function is meant to return the maximum value in vec, which contains len entries.

further to my commentsl, try this

max gets seeded with the first value, with an optimisation that ignores the loop if there's only one value in the array - technically not needed, the compiler optimiser will build the for loop to essentially do the same thing

i'm assuming the caller is checking for zero values

float max(float vec[], int len)
{
 // seed max with the first value
 float max=vec[0];
 // short cut
 if(len>1)
 {
  for (int i = 0; i < len; i++) 
  {
   if (vec[i] > max) 
   {
    max = vec[i];
   } 
  }
 }
 return max; 
}