2. 3.18 (Sales-Commission Calculator) One large chemical company pays its salespeople on a com- mission basis. The salespeople receive $200 per week plus 9% of their gross sales for that week. For example, a salesperson who sells $5000 worth of chemicals in a week receives $200 plus 9% of $5000, or a total of $650. Develop a program that will input each salesperson's gross sales for last week and will calculate and display that salesperson's earnings. Process one salesperson's figures at a time. Here is a sample input/output dialog: Enter sales in dollars (-1 to end): 5000.00 Salary is: $650.00 Enter sales in dollars (-1 to end): 1234.56 Salary is: $311.11 Enter sales in dollars (-1 to end): -1 3. 4.16 (Triangle-Printing Program) Write a program that prints the following patterns separately, one below the other. Use for loops to generate the patterns. All asterisks (*) should be printed by a single printf statement of the form printf("%s", "*"); (this causes the asterisks to print side by side). (Hint: The last two patterns require that each line begin with an appropriate number of blanks.] (C) stress sest ste