In this lesson, you learned about many of Visual C++'s operators. You saw the following:
Project 4 Listing. An introduction to operators and if testing.
1:// Filename: PROJECT4.CPP
2:// Computes a tax amount for the tax preparer's client
3:#include <iostream.h>
4:
5:void main()
6:{
7: float earnings;
8: float taxOwed = 0.00; // Stays zero unless changed
9: // in computations
10:
11: cout << "Tax Time!" << endl; // Title
12: cout << "---------" << endl << endl;
13:
14: cout << "How much did the client earn? ";
15: cin >> earnings;
16:
17: if ((earnings < 0.0) || (earnings > 999999.99))
18: {
19: cout << "I believe that you made a mistake. Try again."
20: << endl;
21: return; // Return early to QuickWin
22: }
23:
24: if (earnings > 20000.00)
25: {
26: taxOwed = (earnings - 20000.00F) * .28F;
27: taxOwed += (9999.99F * .20F); // 20% for $10K to 19.9K
28: taxOwed += (4999.99F * .10F); // 10% for $5K to 9.9K
29: }
30:
31: if ((earnings >= 10000.00) && (earnings < 20000.00))
32: {
33: taxOwed = (earnings - 10000.00F) * .20F;
34: taxOwed += (4999.99F * .10F); // 10% for $5K to 9.9K
35: }
36:
37: if ((earnings >= 4999.99) && (earnings < 10000.00))
38: {
39: taxOwed = (earnings - 4999.99F) * .10F;
40: }
41:
42: cout.precision(2);
43: cout.setf(ios::fixed);
44: cout.setf(ios::showpoint);
45: cout << endl << "The client owes a total of " << taxOwed
46: << " in taxes.";
47:
48: return;
49:}
Output
Tax Time! --------- How much did the client earn? 13443.50 The client owes a total of $1188.70 in taxes. Tax Time! --------- How much did the client earn? 28734.99 The client owes a total of $4945.79 in taxes.
Description
1: A C++ comment that includes the program's filename.
2: A C++ comment that describes the program.
3: Include the definitions for using cin and cout.
4: Blank lines make the program more readable.
5: All functions have names, and the first function in all C++ programs is main().
6: All functions begin with a left brace.
7: Defines a floating-point variable that will hold the client's earnings.
8: Defines a floating-point variable that will hold the client's computed tax.
9: When continuing a comment on a second line, you need to use the comment symbol again.
10: Extra blank lines make your program more readable.
11: A printed title helps describe the program to the user.
12: Dashes underline the title.
13: Extra blank lines make your program more readable.
14: A prompt for the client's total earnings amount.
15: Gets the earnings from the user and stores them in earnings.
16: Extra blank lines make your program more readable.
17: Checks whether the user entered an earnings value between $0.01 and $999,999.99.
18: Opening brace starts the if processing.
19: Prints an error message.
20: A new line to tidy the output.
21: Returns to QuickWin to finish.
22: The closing brace terminates the body of the if block.
23: Extra blank lines make your program more readable.
24: Checks whether the earnings are more than $20,000.
25: Opening brace starts the if processing
26: Computes a 28% rate on all earnings over $20,000.
27: Computes a 20% rate on earnings from $10,000 to $19,999.99.
28: Computes a 10% rate on earnings from $5,000 to $9,999.99.
29: The closing brace terminates the if's body.
30: Extra blank lines make your program more readable.
31: Checks whether the earnings are between $10,000 and $19,999.99.
32: Opening brace starts the if processing
33: Computes a 20% rate on earnings from $10,000 to $19,999.99.
34: Computes a 10% rate on earnings from $5,000 to $9,999.99.
35: The closing brace terminates the if's body.
36: Extra blank lines make your program more readable.
37: Checks whether the earnings fall between $5,000 and $9,999.00.
38: Opening brace starts the if processing.
39: Computes a tax rate of 10% on all earnings of $5,000.00 or more.
40: The closing brace terminates the if's body.
41: Extra blank lines make your program more readable.
42: Sets the precision for output to 2 decimal places.
43: Sets the output format to fixed format rather than exponent.
44: Makes sure the decimal point is always shown.
45: Prints the amount of tax computed. A zero remains in earnings if all of the if tests were false.
46: Divide very long statements over several lines to make it more readable.
47: Extra blank lines make your program more readable.
48: Return to QuickWin.
49: main()'s closing brace terminates the program.
8: The initial value is zero and remains zero only if the earnings are less than $5,000.
11: Put a title at the top of your screens so that the user knows exactly what the program is about to do.
17: If the earnings don't fall between $0.01 and $999,999.99, the program assumes that there's a problem with the user's input.
31: Both sides of the && must be true before the body of the if executes.
42: Take care to present your program output neatly to the user.
