Question

C programming

Write the implementation for the three functions described below. The functions are called from the provided main function. You may need to define additional “helper” functions to solve the problem efficiently.

a) Write a print_string function that prints the characters in a string to screen on- by-one.

b) Write a is_identical function that compares if two strings are identical. The functions is required to be case insensitive. Return 0 if the two strings are not identical and 1 if they are identical.

c) Write a is_palindrome function. The function is required to be case insensitive and should only consider the letters and the numbers in the input string, i.e., remove all fillers (see lecture slides). Using this definition, the string “Madam, I’m Adam!” is considered a palindrome. The function is required to return 1 if the string is a palindrome and otherwise 0.

void print_string(char str[]);
int is_identical(char str1[],char str2[]);
int is_palindrome(char str[]);
void main(){
char str1[] = "Hello World";
char str2[] = "Madam, I'm Adam!";
char str3[] = "hello world";
print_string(str1);

Answer 1

#include<stdio.h>

#include<string.h>

#include <ctype.h>

void print_string(char str[]);

int is_identical(char str1[],char str2[]);

int is_palindrome(char str[]);

int main()

{

    char str1[] = "Hello World";

    char str2[] = "Madam, I'm Adam!";

    char str3[] = "hello world";

   

    printf("str1 : ");

    print_string(str1);

   

    printf("str2 : ");

    print_string(str2);

   

    printf("str3 : ");

    print_string(str3);

   

    if( is_identical( str1, str3 ) )

        printf("str1 and str3 are identical.\n");

    else

        printf("str1 and str3 are not identical.\n");

       

    if( is_palindrome( str2 ) )

        printf("str2 is palindrome.\n");

    else

        printf("str2 is not palindrome.\n");

   

    return 0;

}

void print_string(char str[])

{

    int i;

   

    // traverse the string

    for( i = 0 ; i < strlen(str) ; i++ )

        printf("%c", str[i]);

       

    printf("\n");

}

int is_identical(char str1[],char str2[])

{

    // if the length of two string are not equal

    if( strlen(str1) != strlen(str2) )

        return 0;

       

    int i;

       

    // traverse the string

    for( i = 0 ; i < strlen(str1) ; i++ )

    {

        // if the current characters are not equal

        if( tolower(str1[i]) != tolower(str2[i]) )

            return 0;

    }

   

    return 1;

}

int is_palindrome(char str[])

{

    int i, index = 0;

   

    // to store the characters with only letters in small case

    char temp[strlen(str)];

   

    for( i = 0 ; i < strlen(str) ; i++ )

    {

        // isalpha() checks if character is alphabet

        if( isalpha(str[i]) )

            // store the lower case

            temp[index++] = (char)tolower(str[i]);

    }

   

    // terminate the string

    temp[index] = '\0';

   

    // travesre half the string

    for( i = 0 ; i < strlen(temp) / 2 ; i++ )

    {

        // if the i th character from beginning and ending are not equal

        if( temp[i] != temp[strlen(temp) - i - 1] )

            return 0;

    }

   

    return 1;

}

Sample output