Hello all,

I am having a problem with a c++ assignment. The basic problem is that I have two functions -- one to compute the mean and and one to compute the variance of a subarray from a main array -- arraym.I keep getting an extra parameter in call error when I try to compile. Here are my functions:

//mean function
double mean(int arraym[299][299], int minl, int minw, int rlm, int rwm)
{
	double sum(0);
	int n(0);
	for (int x=minl; x<=rlm; x++)
	{
		for (int y=minw; y<=rwm; y++)
			{
				sum += arraym[x][y];
				n++;
			}
	}
	return sum/n;
}

//variance function
double variance(int arraym[299][299], int minl, int minw, int rlm, int rwm)
{
	double sum(0), me;
	int n(0);
	me = mean(arraym, minl, minw, rlm, rwm);
	for (int x=minl; x<=rlm; x++)
	{
		for (int y=minw; y<=rwm; y++)
			{
				sum += (arraym[x][y] - me)*(arraym[x][y] - me);
				n++;
			}
	}
	return sum/(n-1);
}

and here is my function call:

double y;
y = variance(arraym[299][299], minl, minw, rlm, rwm);

any ideas why I would be getting this error? minl and minw are the starting sub-array offsets and rlm and rwm are the ending sub-array offsets. Everything else is declared correctly elsewhere in my code.

Thanks in advance

You just need to change

variance(arraym[299][299], minl, minw, rlm, rwm);

to

variance(arraym, minl, minw, rlm, rwm);

This compiles for me:

#include <cstdlib>
#include <iostream>
#include <string>

//mean function
double mean(int arraym[299][299], int minl, int minw, int rlm, int rwm)
{
  double sum(0);
  int n(0);
  for (int x=minl; x<=rlm; x++)
  {
    for (int y=minw; y<=rwm; y++)
      {
        sum += arraym[x][y];
        n++;
      }
  }
  return sum/n;
}

//variance function
double variance(int arraym[299][299], int minl, int minw, int rlm, int rwm)
{
  double sum(0), me;
  int n(0);
  me = mean(arraym, minl, minw, rlm, rwm);
  for (int x=minl; x<=rlm; x++)
  {
    for (int y=minw; y<=rwm; y++)
      {
        sum += (arraym[x][y] - me)*(arraym[x][y] - me);
        n++;
      }
  }
  return sum/(n-1);
}

int main(int argc, char *argv[])
{
  int arraym[299][299];
  int minl, minw, rlm, rwm;
  double y = variance(arraym, minl, minw, rlm, rwm);
  return 0;
}

thanks a bunch. I had been trying that unsuccessfully but had my mean and variance functions defined after my main code instead of before. I didn`t realize that would make a difference but when I moved them to before the main function it compiled successfully

You can also put

double mean(int arraym[299][299], int minl, int minw, int rlm, int rwm);

(note the addition of the semicolon at the end)

before main, then exactly the same thing you had before after main:

double mean(int arraym[299][299], int minl, int minw, int rlm, int rwm)
{
  double sum(0);
  int n(0);
  for (int x=minl; x<=rlm; x++)
  {
    for (int y=minw; y<=rwm; y++)
      {
        sum += arraym[x][y];
        n++;
      }
  }
  return sum/n;
}
This article has been dead for over six months. Start a new discussion instead.