非常紧急的编程，计算房屋面积，能写几道就几道吧！
3-1 Design an application that displays the number of square feet in a house. Declare and initialize the length and width of the house to 37 and 22, respectively. Go into your source code and change the initialization values. Rerun the application.（计算房屋面积，长为37，宽为22）3-2 Show the output for each of the following data types: int, float, double, and decimal with no digits, 2 digits, and 5 digits to the right of the decimal, plus formatted with currency. You will probably want to declare both an integral and floatingpoint variable to use for your display. Initialize each variable with an appropriate test value. Print one data type per line.
3-3 Write a program that calculates and prints the take-houme pay for a commissioned sales employee. Perform a compile-time initialization and store the name of Jessica Oakley in a variable called employeeName. Jessica received 7% of her total sales. Her federal tax rate is 18%. She contributes 10% to a retirement program and 6% to Social Security. Her sales this week were $28,000. Produce a formatted report showing the amount for each of the computed items. Select appropriate constatnts. After you finish displaying Jessica Oakley’s data, change the values and rerun the application.关于税收的编程
3-4 Write a program that calculates the circumference of a circle. Declare a named constant for PI with a value of 3.1419.计算圆周长的程序
