Unknown symbols when reading file and saving words to an array (iostream)

[MatthiasBerger]

So the task is finding palindromes (symetrical words) from a text file and outputing them to another file. Text can be read only one symbol at a time.

Current code:

#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;

bool symetry(char * x);

int main()
{
    fstream fout("f1.txt", ios::out);
    fstream fin("f.txt", ios::in);
    int i=0;
    char * arr;
    arr=new char[40];
    char symbol;


    if(!fin)cout<<"Unable to open fin"<<endl;
    if(!fout)cout<<"Unable to open fout file"<<endl;

    while(fin)
    {   fin.get(symbol);
        if ( symbol == ' ' || symbol == '!' || symbol == '?' || symbol == '.' || symbol == ',' || symbol == '(' ||symbol == ')' )
        {
        cout<<"Stoping at "<<arr<<endl;
        if(symetry(arr))cout<<"Symetrical word has been found: "<<arr<<endl;

        fout.write(arr,strlen(arr)-1);
        fout<<flush;
        arr[0] = '\0';
        i=0;}

        else

        {
        arr[i]=symbol;
        i++;}


    }
    delete[]arr;
    fin.close();
    fout.close();

    return 0;
}


bool symetry(char * x)
{
for(int y=0,z=strlen(x)-1;z>y;y++,z--)
{   cout<<x[y]<<" is being compared to "<<x[z]<<endl;
    if (x[y]!=x[z]) return false;
}
return true;
};

Output when input file contains "akka alfa beta ala". The output symbols after the real words change randomly when executing.

Stoping at akkał)y
a is being compared to y
Stoping at alfał)y
a is being compared to y
Stoping at betał)y
b is being compared to y

Process returned 0 (0x0)   execution time : 0.044 s
Press any key to continue.

How to get rid of those symbols so I can actually find the symetry?
Or perhaps I should go some different route to achieve the task stated in the beginning?

[histrungalot]

Just add null terminator. This way the string is terminated and strlen works. But if you don't have a space at the end of the line you won't process the last word. Do you need to process the data one character at a time?

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while(fin) { fin.get(symbol); if ( symbol == ' ' || symbol == '!' || symbol == '?' || symbol == '.' || symbol == ',' || symbol == '(' ||symbol == ')' ) { arr[i] = '\0'; // <----------------------- Added null terminator cout<<"Stoping at "<<arr<<endl;

$ ./a.out Stoping at akka a is being compared to a k is being compared to k Symetrical word has been found: akka Stoping at alfa a is being compared to a l is being compared to f Stoping at beta b is being compared to a Stoping at ala a is being compared to a Symetrical word has been found: ala $

[MatthiasBerger]

Figured that out aswell while waiting for a response :> Also - yes it is a requirment to process the data one character at a time, even the main goal of the task I guess.

Current code (also ends the array when eof is reached now):

#include <iostream>
#include <fstream>
#include <cstring>


using namespace std;

bool symetry(char * x);
int main()
{
    fstream fin("f.txt", ios::in);
    fstream fout("f1.txt", ios::out);

    int i=0;
    char * arr;
    arr= new char [40];
    char symbol;


    if(!fin)cout<<"Unable to open input file"<<endl;
    if(!fout)cout<<"Unable to open output file"<<endl;


    while(fin)
    {
        fin.get(symbol);

        if ( fin.eof() || symbol == ' ' || symbol == '!' || symbol == '?'
        || symbol == '.' || symbol == ',' || symbol == '(' ||symbol == ')' )
        {
        arr[i]='\0';
        cout<<endl;
        cout<<"Stoping at '"<<arr<<"' "<<endl;
        if(symetry(arr)&&i>0)
        {cout<<"Symetrical word has been found: "<<arr<<endl;

        fout<<arr<<'\n';
        fout<<flush;
        }
        arr[0] = '\0';
        i=0;
        }

        else

        {
        arr[i]=symbol;
        i++;

        }


    }

    fin.close();
    fout.close();

    return 0;
}


bool symetry(char * x)
{
for(int y=0,z=strlen(x)-1;z>y;y++,z--)
{   cout<<x[y]<<" is being compared to "<<x[z]<<endl;
    if (x[y]!=x[z]) return false;
}
return true;
};

It works quite well but yet another requirment of the task is that the file should be read sequentialy and in my textbook it is defined as

Read the first value from file
WHILE (file hasn't ended)
{
Process the value read
Read the next value from file
} 

Yet if I try to read the value first, then process it inside the while cycle and then read the next value inside it - the program goes into a loop and just keeps on returning

Stoping at ' '

over and over. How to overcome that?

[Incis B]

Here is a copy of my test INPUT file "F.TXT"

The prog has trouble at the end of each line, and finally crashes near the end.

I'll just have to spend some time to figure-it-out. I'm thinking it's the same problem as before - end end of line terminator. ( somewhere)

ala ddd iffi abbba abbcbba
this file is used with Palindromes
akka alfa abbxbba abbybba abbzbba abbabba abbbbba abbcbba aaa
wwwww wwwaww wwwbwww wwwcwww wwwdwww wwwewww
xxxxx nnnnn xxxxxx.,;xxxxxxx xxxxxx.,;xxqqjqqqxxxxpx mmmmm ......
yyyyy
zzzzz

beta
ala
ala
ddd
iffi
abbba
abbcbba

yyyyyyyyyyyyy
zzzzzzzzzzzzz
0000000000000

[MatthiasBerger]

Adding " if (symbol == '\n ' || ...........)" at the part where it checks for the end of the "word" solves the crashing and errors from new lines but still the sequential reading part mentioned before puzzles me. Not sure of what causes that loop if I modify it as in the textbook example

[histrungalot]

Not sure why you would get infinite loop with seeing what you did, but I think this does what you want. I used Incis B input file.

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fin.get(symbol); while(fin) { if ( fin.eof() || symbol == ' ' || symbol == '!' || symbol == '?' || symbol == '\n' || symbol == '.' || symbol == ',' || symbol == '(' ||symbol == ')' ) { arr[i]='\0'; cout<<endl; cout<<"Stoping at '"<<arr<<"' "<<endl; // I put the i check first because if it fails there // is no need to call symetry if(i>0 && symetry(arr)) { cout<<"Symetrical word has been found: "<<arr<<endl; fout<<arr<<'\n'; fout<<flush; } arr[0] = '\0'; i=0; } else { arr[i]=symbol; i++; } fin.get(symbol); }

Stoping at 'ala' a is being compared to a Symetrical word has been found: ala Stoping at 'ddd' d is being compared to d Symetrical word has been found: ddd Stoping at 'iffi' i is being compared to i f is being compared to f Symetrical word has been found: iffi Stoping at 'abbba' a is being compared to a b is being compared to b Symetrical word has been found: abbba Stoping at 'abbcbba' a is being compared to a b is being compared to b b is being compared to b Symetrical word has been found: abbcbba Stoping at 'this' t is being compared to s Stoping at 'file' f is being compared to e Stoping at 'is' i is being compared to s Stoping at 'used' u is being compared to d Stoping at 'with' w is being compared to h Stoping at 'Palindromes' P is being compared to s Stoping at 'akka' a is being compared to a k is being compared to k Symetrical word has been found: akka Stoping at 'alfa' a is being compared to a l is being compared to f Stoping at 'abbxbba' a is being compared to a b is being compared to b b is being compared to b Symetrical word has been found: abbxbba Stoping at 'abbybba' a is being compared to a b is being compared to b b is being compared to b Symetrical word has been found: abbybba Stoping at 'abbzbba' a is being compared to a b is being compared to b b is being compared to b Symetrical word has been found: abbzbba Stoping at 'abbabba' a is being compared to a b is being compared to b b is being compared to b Symetrical word has been found: abbabba Stoping at 'abbbbba' a is being compared to a b is being compared to b b is being compared to b Symetrical word has been found: abbbbba Stoping at 'abbcbba' a is being compared to a b is being compared to b b is being compared to b Symetrical word has been found: abbcbba Stoping at 'aaa' a is being compared to a Symetrical word has been found: aaa Stoping at 'wwwww' w is being compared to w w is being compared to w Symetrical word has been found: wwwww Stoping at 'wwwaww' w is being compared to w w is being compared to w w is being compared to a Stoping at 'wwwbwww' w is being compared to w w is being compared to w w is being compared to w Symetrical word has been found: wwwbwww Stoping at 'wwwcwww' w is being compared to w w is being compared to w w is being compared to w Symetrical word has been found: wwwcwww Stoping at 'wwwdwww' w is being compared to w w is being compared to w w is being compared to w Symetrical word has been found: wwwdwww Stoping at 'wwwewww' w is being compared to w w is being compared to w w is being compared to w Symetrical word has been found: wwwewww Stoping at 'xxxxx' x is being compared to x x is being compared to x Symetrical word has been found: xxxxx Stoping at 'nnnnn' n is being compared to n n is being compared to n Symetrical word has been found: nnnnn Stoping at 'xxxxxx' x is being compared to x x is being compared to x x is being compared to x Symetrical word has been found: xxxxxx Stoping at '' Stoping at ';xxxxxxx' ; is being compared to x Stoping at 'xxxxxx' x is being compared to x x is being compared to x x is being compared to x Symetrical word has been found: xxxxxx Stoping at '' Stoping at ';xxqqjqqqxxxxpx' ; is being compared to x Stoping at 'mmmmm' m is being compared to m m is being compared to m Symetrical word has been found: mmmmm Stoping at '' Stoping at '' Stoping at '' Stoping at '' Stoping at '' Stoping at '' Stoping at '' Stoping at 'yyyyy' y is being compared to y y is being compared to y Symetrical word has been found: yyyyy Stoping at 'zzzzz' z is being compared to z z is being compared to z Symetrical word has been found: zzzzz Stoping at '' Stoping at 'beta' b is being compared to a Stoping at '' Stoping at 'ala' a is being compared to a Symetrical word has been found: ala Stoping at 'ala' a is being compared to a Symetrical word has been found: ala Stoping at 'ddd' d is being compared to d Symetrical word has been found: ddd Stoping at 'iffi' i is being compared to i f is being compared to f Symetrical word has been found: iffi Stoping at 'abbba' a is being compared to a b is being compared to b Symetrical word has been found: abbba Stoping at 'abbcbba' a is being compared to a b is being compared to b b is being compared to b Symetrical word has been found: abbcbba Stoping at '' Stoping at 'yyyyyyyyyyyyy' y is being compared to y y is being compared to y y is being compared to y y is being compared to y y is being compared to y y is being compared to y Symetrical word has been found: yyyyyyyyyyyyy Stoping at 'zzzzzzzzzzzzz' z is being compared to z z is being compared to z z is being compared to z z is being compared to z z is being compared to z z is being compared to z Symetrical word has been found: zzzzzzzzzzzzz Stoping at '0000000000000' 0 is being compared to 0 0 is being compared to 0 0 is being compared to 0 0 is being compared to 0 0 is being compared to 0 0 is being compared to 0 Symetrical word has been found: 0000000000000

[MatthiasBerger]

The problem was me taking the next symbol in the else part rather than in the main part of the while cycle. Silly me. Everything works as it should now, thank you all for the repsonses :)