Question: Write a function, changename(), which takes a filename as input and produces a filename with a different extension as output in a second string. That is, the input filename string is copied to the output filename string, except that the extension on the latter is changed. The desired new extension should be provided as a third string to the function. Most filenames consist of two parts, the basename (everything to the left of the last '.' character), and the extension (everything to the right of the last '.' character). Often, we wish to name our output files something similar to our input files, and changing the extension is a convenient way to do this. For example, if the input file is called "myprog.in", then an appropriate output file name would be "myprog.out". Write a main program to first read a string (with no spaces in it) from the keyboard. This is the 'input' filename (although we will not actually open this file). The main function then calls changename() to create the 'output' string which, as explained above, is a copy of the input string except that everything after the last .' character is replaced with the extension 'out'. Hint: you can use the function last that you wrote in the previous question to help with this. The input string and the output string are written to a file having the modified filename. For example, if the filename "my.program.in" is entered, the output file my.program.out should contain (and you should test your program using an input filename having more than one '.' character in it, as shown here): input name is my.program.in output name is my.program.out