CODEWITHSUNDEEP
c++functionfstream
DragonClaw
DragonClaw

Reputation: 195

Using fstream Object as a Function Parameter

#include <iostream.h>
#include <fstream.h>
#include <stdlib.h>

void vowel(fstream a){
    char ch;
    int ctr = 0;
    while(!a.eof()){
        a.get(ch);
        if (ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U'){
            cout << ch;
            ctr++;
        }
    }
    cout << "Number of Vowels: " << ctr;
}

main(){
    fstream a;
    a.open("temp.txt", ios::in);
    vowel(a);
return 0;
}

In this simple program , I am trying t count the number of caps Vowels in the file temp.txt. However, I am getting the error:

ios::ios(ios &) is not accessible in function fstream::fstream(fstream&)

Instead opening the file in the function itself does the job. Why is it so? Thanks a lot

NB:

How do I use fstream (specifically ofstream) through a functions parameters

Here it says, that it should work the way I am trying.

Rick

Upvotes: 11

Views: 30273

Answers (3)

Arpit
Arpit

Reputation: 12797

try this. instead of sending the file count the vowels in line.

#include <iostream.h>
#include <fstream.h>
#include <stdlib.h>
int vowels=0;
void vowel(string a){
    char ch;
    int ctr = 0;
int temp=0;
    for(temp=0,temp<a.length();temp++){
        ch=a.at(temp);
        if (ch == 'A' || ch == 'E' || ch == 'I' || ch == 'O' || ch == 'U'){
            cout << ch;
            ctr++;
        }
    }
    vowels+=ctr;
}

main(){
    fstream a;
    a.open("temp.txt", ios::in);

string temp;
while(getline(a,temp))
{
vowel(temp);
function2(temp);
function3(temp);


... so on for more then one functions.

}        
vowel(a);
    return 0;
    }

if you want to pass the file then use the above ans.(pass fstream by reference).

Upvotes: 2

hmjd
hmjd

Reputation: 122011

An fstream object is not copyable. Pass by reference instead: fstream&:

void vowel(fstream& a)

Note you can avoid the call to open() by providing the same arguments to the constructor:

fstream a("temp.txt", ios::in);

and don't use while(!a.eof()), check the result of read operations immediately. The eof() will only be set when an attempt is made to read beyond the last character in the file. This means that !a.eof() will be true when the previous call to get(ch) read the last character from the file, but subsequent get(ch) will fail and set eof but the code won't notice the failure until after it has processed ch again even though the read failed.

Example correct structure:

while (a.get(ch)) {

Upvotes: 16

juanchopanza
juanchopanza

Reputation: 227608

You need to pass the fstream by reference:

void vowel(fstream& a){ .... }
//                ^ here!

Upvotes: 4

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