Question

I need help programming this program in C.

1.) Write a program that reads a message, then checks whether it's a palindrome (the letters in the message are the same from left to right as from right to left), example is shown below:

Enter a message: He lived as a devil, eh?

Palindrome

Enter a message: Madam, I am Adam.

Not a Palindrome

2.) Ignore all characters that aren't letters. Use integer variables to keep track of positions in the array.

3.) It must include and implement the following function prototypes:

• void get_msg(char [], int *);
• bool palindrome(char [], int);

4.) The main() of this program will call get_msg() to obtain only the alphabet characters of the entered message and the total number of alphabet characters of the message. These two data are returned by get_msg() via its two parameters. Here 'alphabet characters' include both upper and lower case of 26 letters only.

• Hint 1: Use getchar() would be easier to process the entered message because it makes easier to catch and test one character a time until Enter is hit. When a character is caught, you would save it in an array only if it is an alphabet character. There are many examples of getchar() in the book, use index to help you to find them if you never use it.
• Hint 2: To check if a character is an alphabet character, you can use isalpha(), which is defined in ctype.h. See p.612-5 for examples.
• Hint 3: C is case sensitive, so, 'a' and 'A' are different characters while they are treated as the same letter in palindromes (i.e., palindromes are case insensitive). You may consider to use toupper() or tolower(), which is also defined in ctype.h, to solve the problem.

5.) This program defines a macro MAX_MSG_LEN with a value of 80, which is used to limit the total alphabet characters that can be saved in an array.

6.) The main() will pass both data received from get_msg() to palindrome(), which returns either true or false, depending on if the array contents is a palindrome. Based on this return, main() prints a simple message, 'Palindrome' or 'Not a palindrome', as shown above.

7.) Please follow all directions.

Answer 1

Code implemented in c

Comments are written for code explanation

Filename: program.c

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

#define MAX_MSG_LEN 80

void get_msg(char message[], int *length);
bool palindrome(char message[], int length);

void get_msg(char message[], int *length){
char ch;
int count = 0;

printf("Enter a message: ");
while((ch = getchar()) != EOF && ch != '\n') {
if (tolower(ch) >= 'a' && toupper(ch) <= 'z'){
message[count] = tolower(ch);
count++;
}
}
*length = count;
}

bool palindrome(char message[], int length){
char *ptr_start = message, *ptr_end = ptr_start + length - 1;

while(ptr_start < ptr_end){
if (*ptr_start++ != *ptr_end--)
return false;
}
return true;
}

int main(void){
char message[MAX_MSG_LEN];
int *length = (int*)malloc(sizeof(message));
get_msg(message, length);
printf("%salindrome\n", palindrome(message, *length) ? "P" : "Not a p");
free(length);
return 0;
}

Code Screenshots:

Working Code Output Screenshots:

If you like my answer, hit thumbs up. Thank you.