Errors overloading the << operator.

[smdelanc]

I got the following errors from my code, and im not sure why any suggestions would be nice and i dont need the super technical explanation why but if you know why mine isn't working id like to know. I don't need to make the operator<< function a friend function do I.

In file included from BigInt.cc:2:
BigInt.h:27: error: expected init-declarator before '&' token
BigInt.h:27: error: expected `,' or `;' before '&' token
BigInt.cc:37: error: `std::ostream& BigInt::operator<<(std::ostream&, BigInt&)' must take exactly one argument
BigInt.cc:37: error: no `std::ostream& BigInt::operator<<(std::ostream&, BigInt&)' member function declared in class `BigInt'
BigInt.cc: In member function `std::ostream& BigInt::operator<<(std::ostream&, BigInt&)':
BigInt.cc:38: error: expected `;' before ')' token


here is the code i left out the implementation of some methods that are unrelated since they are fairly lengthy.

// this is my header file
#ifndef _BIGINT_H
#define _BIGINT_H

class BigInt{

private:
int* data;
int size;

public:
BigInt::BigInt(int s, int d[]);
BigInt BigInt::operator+(const BigInt& b);
// BigInt BigInt::operator*(const BigInt& b);
BigInt BigInt::operator-(const BigInt& b);

bool BigInt::operator<(const BigInt& b);
bool BigInt::operator>(const BigInt& b);

}
std::ostream& BigInt::operator<<(std::ostream& outs, BigInt& a);
#endif /* _BIGINT_H */


// this is my implementation file
#include <iostream>
#include "BigInt.h"
#include <stdlib.h>
#include <stdio.h>
using namespace std;

// i ommitted the implementation for all the other methods but i had them all
// here before the operator<< method.

ostream& BigInt::operator<<(ostream& outs, BigInt& a)
{
for(int i = 0; i < a.size,i++)
{
outs<<a.data[i];
}
return outs;
}

int main()
{
int s;
int *d;
cout<<"enter a size\n";
cin>> s;
char input[s];
cout<<"Enter a big integer.\n";
cin>> input;
d = new int[s];
for(int i = 0; i < s; i++)
{
d[i] = input[i];
}
BigInt *a = new BigInt(s,d);
}

[Duthomhas]

Please use code tags. I can't diagnose your problems because the line numbers listed are beyond the EOF for the .h file you posted.

In the << overload, you accidentally put a semicolon (;) in the for statement instead of a comma (,).
The prototype should be:
std::ostream& operator << (std::ostream& outs, BigInt& a)
and yes, it needs to be a friend of the BigInt class.

In the .h file, you don't need to use BigInt:: before class names. That is implied.

class BigInt {
  ...
  public:
    BigInt(int s, int d[]);
    BigInt operator+(const BigInt& b);
    ...
  };

Hope this helps.

[smdelanc]

for future reference how do i use code tags?

[Duthomhas]

Click the big "Insert Code" button and stick your code between the tags.

Were you able to solve your problem?

[smdelanc]

nope, made some changes to the header to remove the scope operator. but is still have the following errors

In file included from BigInt.cc:2:
BigInt.h:27: error: expected init-declarator before '&' token
BigInt.h:27: error: expected `,' or `;' before '&' token
BigInt.cc:37: error: expected unqualified-id before "friend"
BigInt.cc:37: error: expected init-declarator before "friend"
BigInt.cc:37: error: expected `,' or `;' before "friend"

they all exist on these two lines

line27 from .h

std::ostream& friend operator<<(std::ostream& outs, const BigInt& a);

line37 from .cc

ostream& friend BigInt::operator<<(ostream& outs,const BigInt& a)

here is the whole header now

#ifndef _BIGINT_H
#define	_BIGINT_H

class BigInt{

private:
    int* data;
    int size;
    
public:
    BigInt(int s, int d[]);
    BigInt operator+(const BigInt& b);
//    BigInt operator*(const BigInt& b);
    BigInt operator-(const BigInt& b);
    
    bool operator<(const BigInt& b);
    bool operator>(const BigInt& b);
    
}
std::ostream& friend operator<<(std::ostream& outs, const BigInt& a);
#endif	/* _BIGINT_H */ 

and my other code with some functions removed

#include "BigInt.h"
#include <stdlib.h>
#include <stdio.h>
#include <iostream>
using namespace std; 

ostream& friend BigInt::operator<<(ostream& outs,const BigInt& a)
{
    for(int i = 0; i < a.size; i++)
    {
        outs<<a.data[i];
    }
    return outs;
}

int main()
{
    int s;
    int *d;
    cout<<"enter a size\n";
    cin>> s;
    char input[s];
    cout<<"Enter a big integer.\n";
    cin>> input;
    d = new int[s];
    for(int i = 0; i < s; i++)
    {
        d[i] = input[i];
    }
    BigInt *a = new BigInt(s,d);
}

[Duthomhas]

Ahh, you need to include the appropriate files:

#ifndef _BIGINT_H
#define	_BIGINT_H

#include <iostream>

class BigInt{
...

It is complaining because it doesn't know what "ostream" is.

Hope this helps.

[smdelanc]

ya i included that and it didn't change anything. got any other ideas?

[Duthomhas]

You included it in your BigInt.h file like I showed you?