Function replace_substring 

pub fn replace_substring(
    string: &str,
    begin: i32,
    end: i32,
    replacement: char,
) -> String

Replaces a range of characters in string with the given replacement. The range is begin to end.

• begin –> inclusive
• end –> exclusive

The string with the replaced substring gets returned.

Example:

 let input: &str = "Hello, World!";
 let result: String = funny_string::replace_substring(input, 1, 5, 'X');
 // result now contains the string "HXXXX, World!"