problem5.c

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

int is_vowel(int ch)
{
    switch (ch)
    {
    case 'a':
    case 'e':
    case 'i':
    case 'o':
    case 'u':
    case 'A':
    case 'E':
    case 'I':
    case 'O':
    case 'U':
        return 1;
    }
    return 0;
}
int main(void)
{
    char wrong[50], right[50];
    int i, j;
    FILE *fptr1, *fptr2;

    if ((fptr1 = fopen("wrong.txt", "r")) == NULL)
    {
        printf("Error in openning file\n");
        exit(1);
    }
    if ((fptr2 = fopen("right.txt", "w")) == NULL)
    {
        printf("Error in openning file\n");
        exit(1);
    }
    while ((fgets(wrong, 100, fptr1)) != NULL)
    {
        i = j = 0;
        while (wrong[i] != '\0')
        {
            if (islower(wrong[i]) && (i == 0 || wrong[i - 1] == '.'))
                right[j++] = toupper(wrong[i++]);
            else if (wrong[i] == ' ' && wrong[i - 1] == 'a' && is_vowel(wrong[i + 1]))
            {
                right[j++] = 'n';
                right[j++] = wrong[i++];
            }
            else
                right[j++] = wrong[i++];
        }
        right[j] = '\0';
        fputs(right, fptr2);
    }
}