Write a program to convert a string (of up to 20 characters, including the terminating null character) to all uppercase characters. After getting a string that could include spaces (use the fgets() function and don't forget to strip off the ending if it is there), display the original string. Pass the string to a void function (since the 'string' is really as character array) and have the function convert the string to all uppercase by iterating through the string using a for loop and the strlen() function (which is part of the string. h library), and using the toupper() function (which is part of the ctype. h library) to convert each character in the string. Then, back in the main program, display the all uppercase string.