Write C programs named mystring.h and mystring.c, containing the headers and implementations of the following functions.

1. int letter_count(char *s) computes and returns the number of English letters in string s.
2. int word_count(char *s) computes and returns the number of words in string s.
3. void lower_case(char *s) changes upper case to lower case of string s.
4. void trim(char *s) removes the unnecessary empty spaces of string s.

mystring.h

#include 

int letter_count(char *);

void lower_case(char *);

int word_count(char *);

void trim(char *);

mystring.c

#include "mystring.h"

int letter_count(char *s) 

{

// your implementation

}

void lower_case(char *s) {

// your implementation

}

int word_count(char *s) {

// your implementation

}

void trim(char *s) {

// your implementation

}

Use the provided main function to test the above functions.

#include "mystring.h"

int main(int argc, char* args[]) {

 setbuf(stdout, NULL);

 char str[100] = " This Is a Test ";

 printf(" Input string: \"%s\"", str);

 printf(" Letter count:%d", letter_count(str));

 printf(" Word count:%d", word_count(str));

 trim(str);

 printf(" After trimming:\"%s\"", str);

 lower_case(str); 

 printf(" After lower case:\"%s\"", str);

 return 0;

}

output should look like this:

Input string: " This Is a Test "

Letter count:11

Word count:4

After trimming:"This Is a Test"

After lower case:"this is a test"