PorterStemming.cpp

#include <iostream> // std::cin, std::cout
#include <fstream> // std::ifstream
#include<string.h>
#include<stdlib.h>
#include<ctype.h>
#include <stdio.h>

using namespace std;

static int k0,k;
static char *b;
char temp[20];
char add_array[5];
static int parameter;

/*Function to check individually for consonants and vowels.
Vowels here are: a,e,i,o,u and y preceded by a consonant.
k0 here is the first element.
*/

int cons(char a[],int i)
{
    switch (a[i])
    { case 'a': case 'e': case 'i': case 'o': case 'u': return 0;
    case 'y': {if (i==k0) return 1; else !cons(a,i-1);}
    default: return 1;
    }
}


/*
If C- consonant sequence (c,cc,ccc,ccc,..)
V- vowel sequence (v, vv, vvv,...)
This function m() gives the count of (VC) formed.
Example
m=0 TR, EE, TREE, Y, BY.
m=1 TROUBLE, OATS, TREES, IVY.
m=2 TROUBLES, PRIVATE, OATEN, ORRERY.
*/

int m(char a[],int j,int k)
{
    int n = 0;
    int r = k0;
    int flag;
    int c=0;
    int v=0;
    int value1=0;
    int value2=0;
    int value=0;
    int loop=0;
    while (1)
    {

        while(r<=k)
        {
            {

                if (r > j) break;
                if (! cons(a,r)) {c++; value1=1; break;} /*checks for vowel*/
                r++;
            }
            if (value1==1) break;
        }
        value1=0;
        r++;


        while(r<=k)
        {
            {

                if (r > j) break;
                if (cons(a,r)) {v++; value2=1; break;} /*checks for consonant*/
                r++;
            }
            if (value2==1) break;
        }
        value2=0;
        r++;
        if ((c==v)&&(r<=k+1))
        {

            value=value+1;c=0;v=0; /*counts the number of VC sequences*/
        }
        if (r>k) break;
    }

    return value; /*returns the value of VC count found out*/

}

/*checks in a word, if it has a vowel*/

int vowelinstem(char a[],int j)
{

    int last_w=j;
    int i;
    for (i = k0; i <= last_w; i++) if (! cons(a,i)) return 1;
    return 0;
}


/*checks for double consonants. Checks for the last position and the last but one-th position. Of the form say -ss */

int doublec(char a[],int j)
{
    int last_w=j;
    if (j < k0+1) return 0;
    if (a[j] != a[j-1]) return 0;
    return cons(a,j);
}

/*Checks for the form CVC*/

int cvc(int i,char a[],int j)
{

    if (i <= k0+2)
    {
        if (!cons(a,i) || cons(a,i-1) || !cons(a,i-2))
        {
            int ch = a[i];
            if (ch == 'w' || ch == 'x' || ch == 'y') return 0; /* In CVC, the last C should not be w,x,y as per the algo.*/
        }
    }
    return 1;
}


/* Readjusts the string as per requirement. Adds new suffixes or changes to different forms as required.*/

void setto(int len_inc,char *add,char a[])
{
    // cout<<"\nI am here now";
    int len3=len_inc;
    if (parameter==1)
    {
        char temp1[15];
        memset(temp1,0,sizeof(temp1)); /*setting temp1 to null*/
        memcpy(temp1,a,k+1); /*copying the contents of array a till the parameter k passed into temp1*/
        memset(a,'\0',sizeof(a)); /*setting a to null. Basically to remove out the junk values when used later in the func*/
        strcpy(a,temp1); /*Copying temp1 to a*/
        //cout<<a;
        parameter=0;
    }
    k+=len_inc;
    strcat(a,add); /*Concatenating the suffix passed. Eg:pon(a)+i(add)=poni(a)*/
    char temp[15];
    memset(temp,0,sizeof(temp));
    memcpy(temp,a,k+1);
    memset(a,0,sizeof(a));
    memcpy(a,temp,k+1);
    return;
}

/*This part matches the suffix passed and checks if the suffix is present in the word*/

int ends(char a[],char * s,int length, int j)
{
    int last_w;
    int len=length;
    int pos=k-length+1;
    char temp[20];
    memset(temp,0,sizeof(temp));
    for(int m=0;m<=len-1;m++)
            {

        temp[m]=a[pos];
        pos++;
        }
    int r;
    if ((r=strcmp(s,temp))==0){return 1;} /*Compares and returns 1 if suffix found.*/
    else
        return 0;

}


/* step1ab() gets rid of plurals and -ed or -ing. e.g.

caresses -> caress
ponies -> poni
ties -> ti
caress -> caress
cats -> cat

feed -> feed
agreed -> agree
disabled -> disable

matting -> mat
mating -> mate
meeting -> meet
milling -> mill
messing -> mess

meetings -> meet

*/


void step1ab(char a[],int j)
{ //cout<<"Enter 1AB";
    int last_w=j;
    int h=0;
    if (a[k] == 's')
    {
        if (ends(a,"sses",4,last_w)==1) { k-= 2;} else
            if (ends(a,"ies",3,last_w)==1) { k-=3;setto(1,"i",a);} else
                if (a[k-1] != 's') {k--;return;}
    } else
        if (ends(a,"eed",3,last_w)==1) {if (m(a,last_w,k)>1)k--;} else
            if ((ends(a,"ed",2,last_w)==1)||(ends(a,"ing",3,last_w)==1))
            {
                if ((ends(a,"ed",2,last_w)==1)&&vowelinstem(a,last_w)) { k-=2;}
                if ((ends(a,"ing",3,last_w)==1)&&vowelinstem(a,last_w)) {k-=3;}
                j=k;
                
                if (ends(a,"at",2,j)==1) { k-=2;setto(3,"ate",a);} else
                    if (ends(a,"bl",2,j)==1) { k-=2;setto(3,"ble",a);} else
                        if (ends(a,"iz",2,j)==1) { k-=2;setto(3,"ize",a);} else
                            if (doublec(a,k) ) { k--; {int ch=a[k]; if (ch == 'l' || ch == 's' || ch == 'z') k++;}}
            }
            if((ends(a,"at",2,j)==1) && (ends(a,"bl",2,j)==1) && (ends(a,"iz",2,j)==1))
            {
            if (m(a,j,k) == 1 && cvc(k,a,0)) {parameter=1;setto(1,"e",a);}
            }
            return;
}

/*turns terminal y to i when there is another vowel in the stem. */

void step1c(char a[]) {
     //cout<<"Enter 1C";
     //cout<<k;
     
if (ends(a,"y",1,k) && vowelinstem(a,k))
{ parameter=1;
    k-=1;
    setto(1,"i",a);
}}

 
 /* step2() maps double suffices to single ones. so -ization ( = -ize plus
-ation) maps to -ize etc. note that the string before the suffix must give
m() > 0. */

void step2(char a[],int j) {

    if ((m(a,j,k)>0)){
        switch (a[k-1])
        {

        case 'a': if (ends(a,"ational",7,k)) {k-=7; parameter=1;cout<<"The value is "<<" "<<k; setto(3,"ate",a); break; }
                  if (ends(a,"tional",6,k)) {k-=6;setto(4,"tion",a); break; }
                  break;
        case 'c': if (ends(a,"enci",4,k)) { k-=4;parameter=1;setto(4,"ence",a); break; } else
                      if (ends(a,"anci",4,k)) { k-=4;parameter=1;setto(4,"ance",a); break; }
                      break;
        case 'e': if (ends(a,"izer",4,k)) {{k-=4;parameter=1;setto(3,"ize",a); break; }}
                  break;
        case 'l': if (ends(a,"bli",3,k)) {k-=3;parameter=1;setto(3,"ble",a); break; }
                  if (ends(a,"eli",3,k)) {k-=3;setto(1,"e",a); break; }
                  if (ends(a,"alli",4,k)) {k-=4;parameter=1;setto(2,"al",a); break; }
                  if (ends(a,"entli",5,k)) {k-=5;parameter=1;setto(3,"ent",a); break; }
                  if (ends(a,"ousli",5,k)) {k-=5;parameter=1;setto(3,"ous",a); break; }
                  break;
        case 'o': if (ends(a,"ator",4,k)) { k-=4;parameter=1;setto(3,"ate",a); break; }
                  if (ends(a,"ization",7,k)) { k-=7;parameter=1;setto(3,"ize",a); break; }
                  if (ends(a,"ation",5,k)) {k-=5;parameter=1;setto(3,"ate",a); break; }
                  break;
        case 's': if (ends(a,"alism",5,k)) { k-=5;parameter=1;setto(2,"al",a); break; }
                  if (ends(a,"iveness",7,k)) { k-=7;parameter=1;setto(3,"ive",a); break; }
                  if (ends(a,"fulness",7,k)) { k-=7;parameter=1;setto(3,"ful",a); break; }
                  if (ends(a,"ousness",7,k)) { k-=7;parameter=1;setto(3,"ous",a); break; }
                  break;
        case 't': if (ends(a,"aliti",5,k)) { k-=5;parameter=1;setto(2,"al",a); break; }
                  if (ends(a,"iviti",5,k)) { k-=5;parameter=1;setto(3,"ive",a); break; }
                  if (ends(a,"biliti",6,k)) { k-=6;parameter=1;setto(3,"ble",a); break; }
                  break;
        case 'g': if (ends(a,"logi",4,k)) { k-=4;parameter=1;setto(3,"log",a); break; }

        } }}
        
/* step3() deals with -ic-, -full, -ness etc. similar strategy to step2. */

void step3(char a[],int j) {
    if (m(a,j,k)>0){
        switch (a[k])
        {

        case 'e': if (ends(a,"icate",5,k)) { k-=5;parameter=1;setto(2,"ic",a); break; }
                  if (ends(a,"ative",5,k)) { k-=5;parameter=1;setto(0," ",a); break; }
                  if (ends(a,"alize",5,k)) { k-=5;parameter=1;setto(2,"al",a); break; }
                  break;
        case 'i': if (ends(a,"iciti",5,k)) { k-=5;parameter=1;setto(2,"ic",a); break; }
                  break;
        case 'l': if (ends(a,"ical",4,k)) { k-=4;parameter=1;setto(2,"ic",a); break; }
                  if (ends(a,"ful",3,k)) { k-=3;parameter=1;setto(0," ",a); break; }
                  break;
        case 's': if (ends(a,"ness",4,k)) { k-=4;parameter=1;setto(0,"",a); break; }
                  break;
        } }}


/* step4() takes off -ant, -ence etc., in context <c>vcvc<v>,i.e. m()>1. */

void step4(char a[],int j)
{ if ((m(a,j,k)>1))
{ switch (a[k-1])
{ case 'a': if (ends(a,"al",2,k)) {k-=2;parameter=1;setto(0," ",a);return;}
       case 'c': if (ends(a,"ance",4,k)){k-=4;parameter=1;setto(0," ",a);return;}
                 if (ends(a,"ence",4,k)){k-=4;parameter=1;setto(0," ",a);return;}
       case 'e': if (ends(a,"er",2,k)) {k-=2;parameter=1;setto(0," ",a);return;}
       case 'i': if (ends(a,"ic",2,k)){k-=2;parameter=1;setto(0," ",a);return;}
       case 'l': if (ends(a,"able",4,k)){k-=4;parameter=1;setto(0," ",a);return;}
                 if (ends(a,"ible",4,k)){k-=4;parameter=1;setto(0," ",a);return;}
       case 'n': if (ends(a,"ant",3,k)) {k-=3;parameter=1;setto(0," ",a);return;}
                 if (ends(a,"ement",5,k)){k-=5;parameter=1;setto(0," ",a);return;}
                 if (ends(a,"ment",4,k)) {k-=4;parameter=1;setto(0," ",a);return;}
                 if (ends(a,"ent",3,k)) {k-=3;parameter=1;setto(0," ",a);return;}
       case 'o': if (ends(a,"ion",3,k) && (a[k-3] == 's' || a[k-3] == 't')){k-=3;parameter=1;setto(0," ",a);return;}
                 if (ends(a,"ou",2,k)) {k-=2;parameter=1;setto(0," ",a);return;}
       case 's': if (ends(a,"ism",3,k)) {k-=3;parameter=1;setto(0," ",a);return;}
       case 't':
           if (ends(a,"ate",3,k)) {k-=3;parameter=1;setto(0," ",a);return;} //========================discuss
           if (ends(a,"iti",3,k)) {k-=3;parameter=1;setto(0," ",a);return;}
       case 'u': if (ends(a,"ous",3,k)) {k-=3;parameter=1;setto(0," ",a);return;}
       case 'v': if (ends(a,"ive",3,k)) {k-=3;parameter=1;setto(0," ",a);return;}
       case 'z': if (ends(a,"ize",3,k)) {k-=3;parameter=1;setto(0," ",a);return;}
       default: return;
}
if (m(a,j,k) > 1) j=k;
}}

/* step5() removes a final -e if m() > 1, and changes -ll to -l if
m() > 1. */

void step5(char a[],int j)
{
    j = k;
    if (a[k] == 'e')
    { int x = m(a,j,k);
    if (x > 1 ){k--;} else
        if ((x == 1) && !cvc(k-1,a,0)) k--;
    }
    if (m(a,j,k) > 1)
    {
        if (doublec(a,k))
        {
            if (a[k] == 'l') k--;
        }
    }
}

/*Initialisatin and calls all 5 steps. */

int stem(char a[], int i, int j)
{
    k = j; k0 = i; /* copy the parameters into statics */
    if (k <= k0+1) return k;
    step1ab(a,j);
    step1c(a); step2(a,j);
    step3(a,j);
    step4(a,j);
    step5(a,j);

    return k;
}

int main () { /*main and stemfile function.----------------------------------------------*/
    char str[50];
    char str1[50];
    int i=0;
    char *a=new char[15];
    int val;
    int j;char c;
    int x=0;
    static char * s;
    char fin_char;
    string line;
    int warning=0;
    std::cout << "Enter the name of an existing text file to test. \nExample: abc.txt\n: ";
    std::cin.get (str,256); // get c-string
     cout<<"============================================================================="<<endl;
    //std::cout << "Enter the name of an existing output text file: ";
    //std::cin.get (str1,256);
    /*if(argc !=3 )
{
cout << "Bad parameter"<<endl ;
cout << "Example:\n\t" ;
cout << argv[0]<< " "<< "<input file name> <output file name>" << endl ;
return -1;
}*/
    
    // argv[0] --> name of the executable
    // argv[1] --> name of the input file
    // argv[2] --> name of the output file

    //strcpy(str,argv[1]);
    std::ifstream is(str); // open input file
    std::ofstream ofs;
    ofs.open ("testfile_output.txt", std::ofstream::out);
    //std::ifstream out (argv[2]) ; // open output file
    if (is.fail()) {cout<<"\n ERROR: Enter a valid existing filename. Example: abc.txt\n";cout<<"\n";system("pause");}
    else
    {
        while (is.good()) // loop while extraction from file is possible
        { memset(a,'\0',sizeof(a));
            while(is.getline(a,50,'\n'))
            { memset(temp,'\0',sizeof(temp));
                memcpy(temp,a,strlen(a));
                memset(a,0,sizeof(a));
                strcpy(a,temp);
                cout<<"Word in the file:"<<" ";
                puts(a);cout<<endl;
                a[strlen(a)] = '\0' ;
                for (int j=0; j<strlen(a); ++j) //||a[j]=='{'||a[j]=='['||a[j]=='}'||a[j]=']'||a[j]='|'||a[j]='\'||a[j]=='/'||a[j]=='.'
                {
                    if (a[j]=='*'||a[j]=='!'||a[j]=='@'||a[j]=='#'||a[j]=='$'||a[j]=='%'||a[j]=='^'||a[j]=='&'||a[j]=='('||a[j]==')'||a[j]=='{'||a[j]=='['||a[j]=='}'||a[j]=='.'||a[j]=='/'||a[j]=='>'||a[j]=='<'||a[j]==','||a[j]==':'||a[j]==';') if (warning==0){cout<<"\nWarning: Special character found.\nSpecial character remain unaltered.\n"; warning=1;}
                    a[j]=tolower(a[j]);
                }
                cout<<"\nWord in the file after changing case:"<<" ";
                cout <<a<<endl;
                //system("pause");

                int iCount = -1 ;
                iCount = strlen(a) ;
                //j = j-1;
                --iCount ;
                a[stem(a,0,iCount)+1] = 0; //Calling stem function and null terminating the string.
                cout<<"\n";
                cout<<"Stem Word:"<<"\n";
                cout<<a << endl; // write in the ouput file
                cout<<"\n";
                cout<<"============================================================================="<<endl;
                ofs<<a;
                //ofs.write(a,iCount);
                ofs<<endl;
            }

             is.close(); // close input file
             ofs.close() ; // close output file
        }
        system("pause");
        return 0;
    }
}