Please fill in the blanks in C.

Please fill in the blanks in C.

/* Copy Strings Backward

Input String1: Hello World*/

/* We’ll initialize a string (I’ll use “Hello World”). Then, create a
second string and copy the first string over, but backwards, using a loop. Print both strings.
For example: string 1 is “Hello World”, string 2 would be “dlroW olleH”. */

#include<stdio.h>

#define str_len __1__ //str_len = hello + space + world + null char LEN

__2__ print_string(__3__ str[__4__]);

__5__ copy_string(__6__ s1[__7__], __8__ s2[__9__]);

int main()

{

            __10__ str1[]= "Hello World";

            __11__ str2[__12__];

            //loop and copy each character over

            // until the array reaches null character

            copy_string(__13__, __14__);

            //printing back by calling function print_string

            printf("String1: ");

            print_string(__15__);

            printf("\nString2: ");

            print_string(__16__);

}

/*Copy one string to another by looping backward.

Need 2 index variables to keep track of each string.

For ex: string1 = "hello", len = 6 (1 for null character)

string2[0] = string1[4] // letter 'o'

string2[1] = string2[3] // letter 'l'

Notice the index value compare to the len.*/

__17__ copy_string(__18__ s1[__19__], __20__ s2[__21__])

{

            int idx1, idx2 = 0; //this is the index counter for the 2 strings s1 and s2

            /*be careful here. We'll loop from the end of str1 to get letter 'd'

               normally, for array, last character is size-1, but for string,

               the last index is the null character, not the last character*/

            for(idx1= str_len - __22__; idx1 >= __23__ ; idx1 __24__)

            {

                        /*Copy each char from string s1 to string s2*/

                        __25__[__26__] = __27__[__28__];

                        /*idx1 for s1 is updated with for loop

                        update idx2 to save in the next location of s2.*/

                        idx2++;

            }

            //After reading all characters,need to add something in the last

            //index position to let the program knows the string has ended.

            s2[__29__] = '__30__';

}

/*

Printing all letter until the null character is reached.

 printf("%s", str) would work, but we are doing this way

    to make sure we understand how string works.

Loop through all character until it reaches null character*/

__31__ print_string(__32__ str[str_len])

{

            for(int i = 0; str[i] != __33__; i++)

                        printf("%c", __34__);

}