Questions
1. Dividing a program into functionsa. is the key to object-oriented programming.
b. makes the program easier to conceptualize.
c. may reduce the size of the program.
d. makes the program run faster.
Answer: b,c
2. A function name must be followed by ________.
Answer: parentheses
3. A function body is delimited by ________.
Answer: braces { }
4. Why is the main() function special?
Answer: It’s the first function executed when the program starts
5. A C++ instruction that tells the computer to do something is called a ________.
Answer: statement
6. Write an example of a normal C++ comment and an example of an old-fashioned /* comment.
Answer:
// this is a comment
/* this is a comment */
7. An expression
a. usually evaluates to a numerical value.
b. indicates the emotional state of the program.
c. always occurs outside a function.
d. may be part of a statement.
Answer:a, d
8. Specify how many bytes are occupied by the following data types in a 32-bit system:
a. Type int
b. Type long double
c. Type float
d. Type long
Answer:
a. 4
b. 10
c. 4
d. 4
9. True or false: A variable of type char can hold the value 301.
Answer: false
10. What kind of program elements are the following?
a. 12
b.‘a’
c. 4.28915
d. JungleJim
e. JungleJim()
Answer:
a. integer constant
b. character constant
c. floating-point constant
d. variable name or identifier
e. function name
11. Write statements that display on the screen
a. the character ‘x’
b. the name Jim
c. the number 509
Answer:
a.cout << ‘x’;
b. cout << “Jim”;
c. cout << 509;
12. True or false: In an assignment statement, the value on the left of the equal sign is always equal to the value on the right.
Answer: false; they’re not equal until the statement is executed
13. Write a statement that displays the variable george in a field 10 characters wide.
Answer: cout << setw(10) << george;
14. What header file must you #include with your source file to use cout and cin?
Answer: IOSTREAM
Answer: cin>>temp
16. What header file must you #include with your program to use setw?
Answer: iomanip
17. Two exceptions to the rule that the compiler ignores whitespace are ________ and
________.
Answer: string constants, preprocessor directives
18. True or false: It’s perfectly all right to use variables of different data types in the same arithmetic expression.
Answer: true
19. The expression 11%3 evaluates to ________.
Answer: 2
20. An arithmetic assignment operator combines the effect of what two operators?
Answer: assignment (=) and arithmetic (like + and *)
21. Write a statement that uses an arithmetic assignment operator to increase the value of the variable
temp by 23. Write the same statement without the arithmetic assignment operator.
Answer:
temp += 23;
temp = temp + 23;
22. The increment operator increases the value of a variable by how much?
Answer: 1
23. Assuming var1 starts with the value 20, what will the following code fragment print out?
cout << var1--;
cout << ++var1;
Answer: 2020
24. In the examples we’ve seen so far, header files have been used for what purpose?
Answer: to provide declarations and other data for library functions, overloaded operators,and
objects
Answer: library
Exercises
1. Assuming there are 7.481 gallons in a cubic foot, write a program that asks the user to enter a number of gallons, and then displays the equivalent in cubic feet.
Solution: Question 1
2. Write a program that generates the following table:
1990 135
1991 7290
1992 11300
1993 16200
Use a single cout statement for all output.
Solution: Question 2
3. Write a program that generates the following output:
10
20
19
Use an integer constant for the 10, an arithmetic assignment operator to generate the 20, and a decrements operator to generate the 19.
Solution: Question 3
4. Write a program that displays your favorite poem. Use an appropriate escape sequence for the line breaks. If you don’t have a favorite poem, you can borrow this one by Ogden Nash:
Candy is dandy,
But liquor is quicker.
Solution: Question 4
5. A library function, islower(),takes a single character (a letter) as an argument and returns a nonzero integer if the letter is lowercase, or zero if it is uppercase. This function requires the header file CTYPE.H. Write a program that allows the user to enter a letter, and then displays either zero or nonzero, depending on whether a lowercase or uppercase letter was entered. (See the SQRT program for clues.)
Solution: Question 5
6. On a certain day the British pound was equivalent to $1.487 U.S., the French franc was $0.172, the German deutsche mark was $0.584, and the Japanese yen was $0.00955. Write a program that allows the user to enter an amount in dollars, and then displays this value converted to these four other monetary units.
Solution: Question 6
7. You can convert temperature from degrees Celsius to degrees Fahrenheit by multiplying by 9/5 and adding 32. Write a program that allows the user to enter a floating-point number representing degrees
Celsius, and then displays the corresponding degrees Fahrenheit.
Solution: Question 7
8. When a value is smaller than a field specified with setw(),the unused locations are, by default, filled in with spaces. The manipulator setfill() takes a single character as an argument and causes this character to be substituted for spaces in the empty parts of a field. Rewrite the WIDTH program so that the characters on each line between the location name and the population number are filled in with periods instead of spaces, as in Port City.....2425785
Solution: Question 8
9. If you have two fractions, a/b and c/d, their sum can be obtained from the formula
a c a*d + b*c
--- + --- = -----------
b d b*d
For example, 1/4 plus 2/3 is
1 2 1*3 + 4*2 3 + 8 11
--- + --- = ----------- = ------- = ----
4 3 4*3 12 12
Write a program that encourages the user to enter two fractions, and then displays their sum in fractional form. (You don’t need to reduce it to lowest terms.) The interaction with the user might look like this:
Enter first fraction: 1/2
Enter second fraction: 2/5
Sum = 9/10
You can take advantage of the fact that the extraction operator (>>) can be chained to read in more than one quantity at once: cin >> a >> dummychar >> b;
Solution: Question 9
10. In the heyday of the British empire, Great Britain used a monetary system based on pounds, shillings, and pence. There were 20 shillings to a pound, and 12 pence to a shilling. The notation for this old system used the pound sign, £, and two decimal points, so that, for example, £5.2.8 meant 5 pounds, 2 shillings, and 8 pence. (Pence is the plural of penny.) The new monetary system, introduced in the 1950s, consists of only pounds and pence, with 100 pence to a pound (like U.S. dollars and cents). We’ll call this new system decimal pounds. Thus £5.2.8 in the old notation is £5.13 in decimal pounds (actually £5.1333333). Write a program to convert the old pounds-shillings-pence format to decimal
pounds. An example of the user’s interaction with the program would be
Enter pounds: 7
Enter shillings: 17
Enter pence: 9
Decimal pounds = £7.89
In most compilers you can use the decimal number 156 (hex character constant ‘\x9c’) to represent the pound sign (£). In some compilers, you can put the pound sign into your program directly by pasting it from the Windows Character Map accessory.
Solution: Question 10
11. By default, output is right-justified in its field. You can left-justify text output using the
manipulator setiosflags(ios::left). (For now, don’t worry about what this new notation
means.) Use this manipulator, along with setw(), to help generate the following output:
Last name First name Street address Town State
-----------------------------------------------------------
Jones Bernard 109 Pine Lane Littletown MI
O’Brian Coleen 42 E. 99th Ave. Bigcity NY
Wong Harry 121-A Alabama St. Lakeville IL
Solution: Question 11
12. Write the inverse of Exercise 10, so that the user enters an amount in Great Britain’s new decimal-pounds notation (pounds and pence), and the program converts it to the old pounds-shillings-pence notation. An example of interaction with the program might be
Enter decimal pounds: 3.51
Equivalent in old notation = £3.10.2.
Make use of the fact that if you assign a floating-point value (say 12.34) to an integer variable, the decimal fraction (0.34) is lost; the integer value is simply 12. Use a cast to avoid a compiler warning. You can use statements like
float decpounds; // input from user (new-style pounds)
int pounds; // old-style (integer) pounds
float decfrac; // decimal fraction (smaller than 1.0)
pounds = static_cast<int>(decpounds); // remove decimal fraction
decfrac = decpounds - pounds; // regain decimal fraction
You can then multiply decfrac by 20 to find shillings. A similar operation obtains pence.
Solution: Question 12
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