Question

Write a program palind.c that reads a message, then checks whether it's palindrome (the letters in the message are the same from left to right as from right to left): Enter a message He lived as a devil, eh? Palindrome Enter a message Madam, I am Adam Not a palindrome Ignore all characters that aren't letters. Use integer variables to keep track of positions in the array. Revise the program in Part I to use a pointer instead of an integer to keep track of positions in the array. Name the new C program as palindP.c.

Answer 1

Here is the code for you:

#include <stdio.h>
#include <ctype.h>
#include <string.h>
int isLinePalindrome(char *line)
{
    int length = strlen(line);
    int i = 0, j = length-1;
    while(i <= j)
    {
       //printf("%c\t%c\n", *(line + i), *(line + j));
       if(!isalpha(*(line + i)))
           i++;
          
       else if(!isalpha(*(line + j)))
           j--;
       else if(tolower(*(line + i)) != tolower(*(line + j)))
           return 0;
       else
       {
          i++;
           j--;  
       }  
    }
    return 1;
}
int main()
{
    char line[50];
    printf("Enter a message: ");
    scanf("%[^\n]s", line);
    printf("You entered %s\n", line);
    if(isLinePalindrome(line))
        printf("Palindrome\n");
    else
        printf("Not a palindrome\n");  
}

And the output screenshot is: