Fortran Function explanation

c#, fortran, function

Solution

      FUNCTION POLY(N,A,X)      ! implicitly real (float) function poly(int n,int a,real x)
      DIMENSION A(N)            ! shape A as 1d array of n values in this scope
C                               ! say nothing (blank comment)
      POLY    = 0.              ! initialise return variable to float value 0
      L       = N               ! set L (implicitly integer) to n
      DO 1 K  = 1,N             ! for(int k=1; k<=n; ++k)
      POLY    = POLY*X + A(L)   !    update return variable
1     L       = L-1             !    decrement L
      RETURN                    ! return current value for poly
      END

so in c-like syntax:

float poly(int n, int a, float x) {
    // redim a(n)
    float result = 0;
    int l = n;
    for(int k=1; k <= n; ++k) {
        result = result*x + a(l);
        --l;
    }
    return result;
}

The bit that doesn't translate is redimensioning A as an array. In C you would pass a pointer and use it as an array, and in C++/C# you'd probably pass a vector-like structure with its own length property.

In C#, using a list:

float poly(List<float> coeffs, float x) {
    float result = 0;
    for(int i=coeffs.Count-1; i >= 0; --i) {
        result = result*x + coeff[i];
    }
    return result;
}

Problem

I have this function in Fortran and i'm trying to recode it in C# ``` C **************************************************************** C FUNCTION POLY C***************************************************************** FUNCTION POLY(N,A,X) DIMENSION A(N) C POLY = 0. L = N DO 1 K = 1,N POLY = POLY*X + A(L) 1 L = L-1 RETURN END C***************************************************************** ``` I found out that `DIMENSION A(N)` creates a vector of `N` values, but we already have a variable `A` from the function parameters, does this means that the array values all equal to `A`? If so then what is the use of `A(N)`. By the way can anyone just explain what does this function do so i can re-implement it in C#

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