/*
 * Pig Latin Filter
 */

#include <stdio.h>
#include <ctype.h>
#include <string.h>

void iglatinpay(char *english);
void strlower(char *string);

int main()
{
    char word[32];
    char *w;
    char ch;
    int count;

    while( (ch = fgetc(stdin)) != EOF)
    {
        if(isalpha(ch))           /* a word starts */
        {
            count=0;
            while(isalpha(ch))    /* read the word */
            {
                word[count] = ch; /* store word */
                count++;
                ch = fgetc(stdin);
            }
            word[count] = '\0';   /* cap word with NULL */
            iglatinpay(word);     /* process the word */

/* This routine displays the word stored in word[] */

            w = word;
            while(*w)
            {
                fputc(*w,stdout);
                w++;
            }

/* Finally, original non-alpha character is displayed */

            fputc(ch,stdout);
        }
        else
            fputc(ch,stdout);     /* non-alpha char */
    }
    return(0);
}

/*
 * This function takes a word (all letters terminated
 * with a NULL) and converts it into pig latin by
 * following some made-up rules. The word is stored
 * in the piglatin[] buffer. Various string routines
 * copy and concatenate parts of the reconstructed
 * word into that buffer. The original starting letter
 * is also saved in a buffer, append[], because only
 * strings can be concatenated to each other, not
 * single chars.
 *
 * A pointer variable saves the original address of
 * the word being translated, so the word is sent and
 * returned as the same variable. This saves going
 * through the pains of returning a string from a
 * function.
 */

void iglatinpay(char *english)
{
    char piglatin[32];      /* temporary word sto. */
    char *e;
    char append[] = "h";    /* first letter sto. */
    char ch;

    e = english;            /* Save starting loc. */

    strlower(english);        /* make it all lowercase */

/*
 * RULES FOR TRANSLATING ENGLISH INTO PIG LATIN
 * As told to a switch-case loop
 *
 * First rule: Words starting with a vowel
 * are merely given the AY ending.
 *
 * Note how strcpy() is used first and then strcat()
 * is used to continue building the pig latin word.
 *
 * Also: See how the case statements "fall through,"
 * enabling several of them to catch common
 * situations.
 */

    ch = *english;
    switch(ch)
    {
        case 'a':
        case 'e':
        case 'i':
        case 'o':
        case 'u':
            strcpy(piglatin,english);
            strcat(piglatin,"ay");
            break;

/*
 * Second rule: Words starting with SH, CH,
 * TH, PH, RH, WH, and QU have both letters 
 * moved to the end before adding AY.
 */

        case 'c':
        case 'p':
        case 'r':
        case 's':
        case 't':
        case 'w':
            if(*(english+1)=='h')
            {
                english+=2;
                strcpy(piglatin,english);
                append[0] = ch;
                strcat(piglatin,append);
                strcat(piglatin,"hay");
                break;
            }
        case 'q':
            if(*(english+1)=='u')
            {
                english+=2;
                strcpy(piglatin,english);
                append[0] = ch;
                strcat(piglatin,append);
                strcat(piglatin,"uay");
                break;
            }

/*
 * Standard rule: Move the first letter to the
 * end of the word and add AY.
 */
                    /* continuing switch-case */
        default:
            english++;
            strcpy(piglatin,english);
            append[0] = ch;
            strcat(piglatin,append);
            strcat(piglatin,"ay");
            break;
    }

    strcpy(e,piglatin);
    *e = toupper(*e);
}

/*
 * Convert a string to lower case. Uses pointers
 * to modify the string elsewhere in memory
 */

void strlower(char *string)
{
    int len,x;

    len= strlen(string);
    for(x=0;x<len;x++)
        *(string+x) = tolower(*(string+x));
}