Thread: Could someone please explain why all the alternatives work?

I am trying to get a better understanding of pointers.
Could someone please explain why all the alternatives work?
And are there any more alternatives?

Code:

#include <stdio.h>


//float summate(float*);// A
//float summate(float[]);// B 
float summate(float z[]);


int main()
{
  float result;
  float a[] = {23.4, 55, 22.6, 3, 40.5, 18};
  result = summate(&a[0]); // could just be summate(a);
  printf("Result = %.2f", result);
  return 0;
}


//float summate(float* x) // C
float summate(float  x[]) 
{
  float sum = 0.0;
  for (int i = 0; i < 6; ++i) 
  {
    sum += x[i];
  }
  return sum;
}