Not declared in this scope Error, Templates

Hey again! I am getting an error with which I am unfamiliar with. It says


hw1prob1.cpp: In function âint main()â:
hw1prob1.cpp:20: error: expected primary-expression before â]â token
hw1prob1.cpp:20: error: âmakeGen2dArrayâ was not declared in this scope
hw1prob1.cpp:32: error: no match for âoperator<<â in âoutFile << *((*(x + ((long unsigned int)(((long unsigned int)third) * 8ul)))) + ((long unsigned int)(((long unsigned int)fourth) * 4ul)))â
hw1prob1.cpp:34: error: no match for âoperator<<â in âoutFile << std::endlâ

In addition, it says no match for the operator << which does not make sense because it is being used by a ifstream.

Code:

#include <iostream>
#include <fstream>

using namespace std;
#include "hw1.h"

int main() 
{
	int** x;
	int value;
	int numRows;
	ifstream inFile;
	inFile.open("matInp.txt");
	numRows = inFile.get();
	int rowSize [numRows];
	for (int i = 0; i < numRows; i++) {
		inFile >> value;
		rowSize[i] = value;
	}
	makeGen2dArray(x, numRows, rowSize[]);
	for (int start = 0; start < numRows; start++) {
		for (int second = 0; second < rowSize[numRows]; second++) {
			inFile >> value;
			x[start][second] = value + 5;
		}
	}
	inFile.close();
	ifstream outFile;
	outFile.open("matOut.txt");
	for (int third = 0; third < numRows; third++) {
		for (int fourth = 0; fourth < rowSize[numRows]; fourth++) {
			outFile << x [third][fourth]*;
		}
			outFile << endl;
	}
	freeGen2dArray(x, numRows);
	return 0;
}

template <class T>
void makeGen2dArray(T ** &x, int numberOfRows, int rowSize[]) {
	x = new T * [numberOfRows];
	for (int i = 0; i < numberOfRows; i++) {
		x[i] = new T [rowSize[i]];
	}
}

template <class T>
void freeGen2dArray(T ** &x, int numberOfRows) {
	for (int i =0; i < numberOfRows; i++) {
		delete [] x[i];

		delete [] x;
		x = NULL;
	}
}

The error occurs in the line that is green. I think it may be a problem with the way I am inputting the parameter but Im not sure. Ive tried different parameter values but nothing seems to work. Any links/tips would be helpful.

Move your functions and templates *above* main...

I have a header file so that should not cause the problem. I just did not put the code here

here it is:

Code:

#ifndef HW1_H
#define HW1_H
#include <vector>

template <class T>
void make2dArray(T ** &x, int numberOfRows, int rowsize[]);
template <class T>
void freeGen2dArray(T ** &x, int numberOfRows);
void addEven2OddLines(std::vector<int>& x, std::vector<int>& y);

#endif

That header also has a conspicuous absence of "makeGen2dArray".

For a template class the definition and implementation must be in the same file.

Jim

Ok so template functions must be declared and implemented in the same file. The other error message still persists however regarding primary expression before a ] token. In addition it is saying that << is not a valid operator in my outFile which is a ifstream object. I checked the syntax and did not find any commas or semicolons out of place which is what other websites said was the issue with that error.

Is this line 34?

Code:

 outFile << x [third][fourth]*;

If it is what is the * for?

Jim

It was intended to dereference the value held in that position of the array but I did not realize the formatting I had put it in already does that. The concept of pointers and a double array is still new to me. I have taken out the * dereference in my code already but I am still getting an error involving no match for a << operator. I have changed the code but the error still persists

Code:

for (int third = 0; third < numRows; third++) {
		for (int fourth = 0; fourth < rowSize[numRows]; fourth++) {
			outFile << x[third][fourth]
					<< " ";
		}
			outFile << "/n";
	}

hw1prob1.cpp:20: error: expected primary-expression before â]â token
hw1prob1.cpp:32: error: no match for âoperator<<â in âoutFile << *((*(x + ((long unsigned int)(((long unsigned int)third) * 8ul)))) + ((long unsigned int)(((long unsigned int)fourth) * 4ul)))â
hw1prob1.cpp:35: error: no match for âoperator<<â in âoutFile << "/n"â

Code:

ifstream outFile;

Just because you called it "outFile" doesn't mean it's the right type.

Where are you assigning memory for x?

Also if the following line hasn't changed what is it doing?

Code:

numRows = inFile.get();

Jim

Originally Posted by tabstop

Code:

ifstream outFile;

Just because you called it "outFile" doesn't mean it's the right type.

Wow you guys are catching my typos left and right. I have spent too many hours straight on this project! I have one last questions and I will leave you all alone if you have the patience. I have been searching around for hours for solutions to the error:

error: expected primary-expression.

In my case the line is:

Code:

	makeGen2dArray(x, numRows, rowSize[]);

where x is declared as int **x;

and the header file that contains the method is

Code:

template <class T>
void makeGen2dArray(T ** &x, int numberOfRows, int rowSize[]) {
	x = new T * [numberOfRows];
	for (int i = 0; i < numberOfRows; i++) {
		x[i] = new T [rowSize[i]];
	}
}

The solutions I have found on involve people typing in types into the function rather than the passing values, constructor misuse, and wrong parameters being passed into the function. In my case, I pass in a reference to a double array known as **x which should be correct, an integer I read from a file, and an array of integers which is also correct.

The specific error says:
hw1prob1.cpp:20: error: expected primary-expression before â]â token


and line 20 is:

Code:

	makeGen2dArray(x, numRows, rowSize[]);

Originally Posted by jimblumberg

Where are you assigning memory for x?

Also if the following line hasn't changed what is it doing?

Code:

numRows = inFile.get();

Jim

The infile object is reading in an integer from the specified file and storing it in the integer named numRows. I looked at the c++ api (not sure what to call in c++) and the method .get() said it read in a char value and stored it as an integer. The first value in the file is a simple integer such as 5 so the get() method should be able to read it into the file.

Code:

rowSize[]

You want to pass the array. Then do so. The array is called "rowSize".

Just made me look like a fool. Thanks. Now time to debug. Thanks for the helpful advice everyone. If you dont mind me asking , is there a good debugger for windows. Currently I have to use putty to remote logon to the unix server and it is a pain to debug this way. Besides putting a virutal linux or linux partition