6. (25pts) Given the string variables str1 and str2 contain "you ought to start with logic" and ou respectively, what is the result of each of the following expressions? a. stri,length() b. str1.find(str2) c. str1.substr(4, 25) d. str1.substr(4, 25).find(str2) e. strl.substr.(str1.find("logic"),3) 7. (8 pts) Given the input data January 25, 2005 and the input statement cin>>string1 >>string2; What is contained in each of the string variables after the statement is executed? 8. (12 pts) Write a C++ program that computes and outputs the area of a circle, given the diameter of the circle. Be sure to use proper formatting and appropriate comments in your code. The output should be labeled clearly