ofil ???

Hey, I'm slugging it out with Stan Lippman (Essential C++) and Stan's winning.

I've included fstream, but when we hit

Code:

---

ofil << "about to call swap!";

---

I get an expected - primary expression error.

Meanwhile I can't find ofil in any of my references. What gives?

- JM

Isn't ofil the identifier given to an ostream in that example?

-JM - post your whole code, and tell us what compiler you're using (that way, if we have the documentation, we can look up the error and get a better description of exactly what the problem is).

okey dokey -

Code:

---

#include<iostream>
#include<vector>
#include<fstream>
using namespace std;


void display( vector<int> vec)
{
    for ( int ix = 0; ix < vec.size(); ++ix)
        cout<<vec[ix]<<' ';
    cout<<endl;
}

void swap( int &val1, int &val2)
{
    std::ofstream ofil<<"swap( "<<val1
        <<", "<<val2<<" )\n";
       
    int temp = val1;
    val1 = val2;
    val2 = temp;
   
    ofil<<"after swap(): val1 "<<val1
        <<" val2: "<<val2<<"\n";
}

ofstream ofil("E:\\text_out1");
void bubble_sort(vector<int> &vec)
{
    for(int ix = 0; ix<vec.size(); ++ix)
        for(int jx = ix+1; jx<vec.size(); ++jx)
            if(vec[ix]>vec[jx]){
            //debugging output
            std::ofstream ofil<<"about to call swap!"
                <<" ix: "<<ix<<" jx: "<<jx<<'\t'
                <<" swapping: "<<vec[ix]
                <<" with "<<vec[jx]<<endl;
                //ok actual swap code...
              swap(vec[ix], vec[jx]);
            }
}

int main()
{
    int ia[8] = {8, 34, 3, 13, 1, 21, 5, 2};
    vector<int> vec(ia, ia+8);
   
    cout<<"vector before sort: ";
    display(vec);
   
    bubble_sort(vec);
   
    cout<<"vector after sort: ";
    display(vec);
   
    cin.get();
    return 0;
}

---

I'm using Dev C++, and I get "expected primary-expression before 'ofil' " and "expected ';' before ofil"

I still don't get it!

- JM

It may be that in the function swap() you are using ofil but you declare it afterwards.

I was really hoping that was it, but no such luck. I still get those errors on all three lines with 'ofil'.

Anybody??

I'm missing something to do with ofstream....

Code:

---

ofstream ofil("E:\\text_out1");

---

put this line just after using namespace std;

in swap

Code:

---

    std::ofstream ofil<<"swap( "<<val1

---

should be

Code:

---

    ofil<<"swap( "<<val1

---

and in bubble_sort

Code:

---

            std::ofstream ofil<<"about to call swap!"

---

should be

Code:

---

            ofil<<"about to call swap!"

---

Kurt

swap() function is coded incorrecvtly. ofil must be an open stream, which it isn't. Sice swap() will be called many many times, suggest you pass it a reference to an open stream.

Quote:

---

Originally Posted by -JM

okey dokey -

Code:

---

#include<iostream>
#include<vector>
#include<fstream>
using namespace std;


void display( vector<int> vec)
{
    for ( int ix = 0; ix < vec.size(); ++ix)
        cout<<vec[ix]<<' ';
    cout<<endl;
}

void swap( int &val1, int &val2, ofstream& ofil)
{
    ofil<<"swap( "<<val1
        <<", "<<val2<<" )\n";
       
    int temp = val1;
    val1 = val2;
    val2 = temp;
   
    ofil<<"after swap(): val1 "<<val1
        <<" val2: "<<val2<<"\n";
}

ofstream ofil("E:\\text_out1");
void bubble_sort(vector<int> &vec, ofstream& ofil)
{
    for(int ix = 0; ix<vec.size(); ++ix)
        for(int jx = ix+1; jx<vec.size(); ++jx)
            if(vec[ix]>vec[jx]){
            //debugging output
            ofil<<"about to call swap!"
                <<" ix: "<<ix<<" jx: "<<jx<<'\t'
                <<" swapping: "<<vec[ix]
                <<" with "<<vec[jx]<<endl;
                //ok actual swap code...
              swap(vec[ix], vec[jx], ofil);
            }
}

int main()
{
    int ia[8] = {8, 34, 3, 13, 1, 21, 5, 2};
    vector<int> vec(ia, ia+8);
   
    cout<<"vector before sort: ";
    display(vec);
    [color=red]ofstream ofil("myfile.txt");   
    bubble_sort(vecofil);
   
    cout<<"vector after sort: ";
    display(vec);
   
    cin.get();
    return 0;
}

---

- JM

---

Thanks guys, now it works -

ZuK, I did just as you said and it works perfectly.

Ancient Dragon, the swap function is straight out of the Lippman book so I didn't change it - maybe it's not coded correctly because it's early in the book?

Anyway, good to go now, thanks a lot!

- JM

You should do what Ancient Dragon says because global variables are baaaad.
Kurt

Code:

---

    bubble_sort(vec[color=red]ofil);

---

'color' undeclared (first use this function)
'red' undeclared (first use this function)

now she no work again

Code:

---

bubble_sort(vec,ofil);

---

OK works again, thanks.