error C2059: syntax error : ']', i cant figure out why this coming up in c++

Question

void display_totals();
int exam1[100][3];// array that can hold 100 numbers for 1st column
int exam2[100][3];// array that can hold 100 numbers for 2nd column
int exam3[100][3];// array that can hold 100 numbers for 3rd column 
int main()
{
    int go,go2,go3;
    go=read_file_in_array;
    go2= calculate_total(exam1[],exam2[],exam3[]);
    go3=display_totals;
    cout << go,go2,go3;
    return 0;
}
void display_totals()
{

    int grade_total;
    grade_total=calculate_total(exam1[],exam2[],exam3[]);
}   
int calculate_total(int exam1[],int exam2[],int exam3[])
{
    int calc_tot,above90=0, above80=0, above70=0, above60=0,i,j;
    calc_tot=read_file_in_array(exam[100][3]);
    exam1[][]=exam[100][3];
    exam2[][]=exam[100][3];
    exam3[][]=exam[100][3];
    for(i=0;i<100;i++);
        {
            if(exam1[i] <=90 && exam1[i] >=100)
                {
                    above90++;
                    cout << above90;
                }
        }
        return exam1[i],exam2[i],exam3[i];

}

int read_file_in_array(int exam[100][3])
{
  ifstream infile;  

  int num, i=0,j=0;
  infile.open("grades.txt");// file containing numbers in 3 columns
    if(infile.fail()) // checks to see if file opended
    {
        cout << "error" << endl;
    }
  while(!infile.eof()) // reads file to end of line
      {
          for(i=0;i<100;i++); // array numbers less than 100
          {
            for(j=0;j<3;j++); // while reading get 1st array or element
            infile >> exam[i][j];
            cout << exam[i][j] << endl;
          }
      }
  infile.close();
  return exam[i][j];
}

Answer 1

The data type you're passing into calculate_total is wrong. C++ is seeing it as a pointer to an int. You're passing in a two dimensional array. You have to make the input type for your calculate_total function match the type of your array.

Also, all those extra []'s are invalid syntax. When passing in a variable defined as an array, pass in only the variable name.

// Invalid function call
f(myArray[]);

// Valid function call
f(myArray);

Inside of the actual function, what are you trying to do? Are you trying to modify an element of exam1, exam2, and exam3 to the value of exam[100][3]?

You're also missing the declaration of the array int exam[100][3]. I don't see it anywhere in your code.

And in the return of calculate_total, your return statement is malformed. You can only return one value, unlike Python where that would return a tuple containing three elements.

Answer 2

I observed the following issues in your code

1. read_file_in_array requires parenthesis. go=read_file_in_array; //Invalid Function Call

2. Passing Arrays as Arguments

3. display_totals requires parenthesis

4. Function prototypes were missing in the beginning

5. display_totals will return nothing. But you are assigning it to a variable

6. I don't understand what this calculate_total function is doing.

If this is your original code, there is a lot of issues in this code. I took this code as it is and compiled using Turbo c++ compiler. I got around 24 errors.

Can you please refactor your code and compile it.