Chapter 3 Input - Output

Chapter 3: Input/Output TRUE/FALSE 1. It is a good idea to redefine cin and cout in your programs. ANS: F PTS: 1 REF: 123 2. In the statement cin >> x;, x can be a variable or an expression. ANS: F PTS: 1 REF: 123 3. The following statements will result in input failure if the input values are not on a separate line. (Assume that x and y are int variables.) cin >> x; cin >> y; ANS: F PTS: 1 REF: 124 4. The number of input data extracted by cin and >> depends on the number of variables appearing in the cin statement. ANS: T PTS: 1 REF: 124 5. The extraction operator >> skips only all leading blanks when searching for the next data in the input stream. ANS: F PTS: 1 REF: 124 6. When reading data into a char variable, after skipping any leading whitespace characters, the extraction operator >> finds and stores only the next character; reading stops after a single character. ANS: T PTS: 1 REF: 125 7. Entering a char value into an int variable causes serious errors, called input failure. ANS: T PTS: 1 REF: 128 8. If input failure occurs in a C++ program, the program terminates immediately and displays an error message. ANS: F PTS: 1 REF: 138 9. In an output statement, each occurrence of endl advances the cursor to the end of the current line on an output device. ANS: F PTS: 1 REF: 142 10. You can use the function getline to read a string containing blanks. ANS: T PTS: 1 REF: 154 MULTIPLE CHOICE 1. Suppose that x is an int variable and y is a double variable and the input is: 10 20.7 Choose the values after the following statement executes: cin >> x >> y;. a. x = 10, y = 20 c. x = 10, y = 20.7 d. x = 10, y = 21.0 b. x = 10, y = 20.0 ANS: C PTS: 1 REF: 123-124 2. Suppose that x and y are int variables. Which of the following is a valid input statement? a. cin >> x >> cin >> y; c. cin << x << y; d. cout << x << y; b. cin >> x >> y; ANS: B PTS: 1 REF: 123-124 3. Suppose that x is an int variable, y is a double variable and ch is a char variable and the input is: 15A 73.2 Choose the values after the following statement executes: cin >> x >> ch >> y; a. b. c. d. x = 15, ch = 'A', y = 73.2 x = 15, ch = 'A', y = 73.0 x = 15, ch = 'a', y = 73.0 This statement results in an error because there is no space between 15 and A. ANS: A PTS: 1 REF: 125-126 4. Suppose that alpha is an int variable and ch is a char variable and the input is: 17 A What are the values after the following statements execute? cin >> alpha; cin >> ch; a. alpha = 17, ch = ' ' b. alpha = 1, ch = 7 ANS: C PTS: 1 c. alpha = 17, ch = 'A' d. alpha = 17, ch = 'a' REF: 126 5. Suppose that x is an int variable, y is a double variable, z is an int variable, and the input is: 15 76.3 14 Choose the values after the following statement executes: cin >> x >> y >> z; a. x = 15, y = 76, z = 14 b. x = 15, y = 76, z = 0 c. x = 15, y = 76.3, z = 14 d. x = 15.0, y = 76.3, z = 14.0 ANS: C PTS: 1 REF: 125-126 6. Suppose that ch1, ch2, and ch3 are variables of the type char and the input is: A B C Choose the value of ch3 after the following statement executes: cin >> ch1 >> ch2 >> ch3; a. 'A' b. 'B' c. 'C' d. '\n' ANS: C PTS: 1 REF: 125-126 7. Suppose that x and y are int variables, z is a double variable, and the input is: 28 32.6 12 Choose the values of x, y, and z after the following statement executes: cin >> x >> y >> z; a. b. c. d. x x x x = = = = 28, 28, 28, 28, ANS: A y y y y = = = = 32, 32, 12, 12, z z z z = = = = PTS: 1 0.6 12.0 32.6 0.6 REF: 125-127 8. Suppose that x is an int variable, ch is a char variable, and the input is: 276. Choose the values after the following statement executes: cin >> ch >> x; a. ch = '2', x = 276 b. ch = '276', x = '.' ANS: B PTS: 1 c. ch = ' ', x = 276 d. ch = 'b', x = 76 REF: 127 9. Suppose that x and y are int variables, ch is a char variable, and the input is: 4 2 A 12 Choose the values of x, y, and ch after the following statement executes: cin >> x >> ch >> y; a. x = 4, ch = 2, y = 12 b. x = 4, ch = A, y = 12 ANS: D PTS: 1 c. x = 4, ch = ' ', y = 2 d. This statement results in input failure REF: 128 10. Suppose that ch1 and ch2 are char variables, alpha is an int variable, and the input is: A 18 What are the values after the following statement executes? cin.get(ch1); cin.get(ch2); cin >> alpha; a. b. c. d. ch1 ch1 ch1 ch1 = = = = 'A', 'A', 'A', 'A', ANS: A ch2 ch2 ch2 ch2 = = = = ' ', alpha = 18 '1', alpha = 8 ' ', alpha = 1 '\n', alpha = 1 PTS: 1 REF: 132 11. Suppose that ch1, ch2, and ch3 are variables of the type char and the input is: A B C What is the value of ch3 after the following statements execute? cin.get(ch1); cin.get(ch2); cin.get(ch3); a. 'A' b. 'B' ANS: B c. 'C' d. '\n' PTS: 1 REF: 132 12. When you want to process only partial data, you can use the stream function ____ to discard a portion of the input. a. clear c. Delete d. Ignore b. skip ANS: D PTS: 1 REF: 133 13.Suppose that alpha, beta, and gamma are int variables and the input is: 100 110 120 200 210 220 300 310 320 What is the value of gamma after the following statements execute? cin >> alpha; cin.ignore(100, '\n'); cin >> beta; cin.ignore(100,'\n'); cin >> gamma; a. 100 b. 200 ANS: C c. 300 d. 320 PTS: 1 REF: 133 14. Suppose that ch1 and ch2 are char variables and the input is: WXYZ What is the value of ch2 after the following statements execute? cin.get(ch1); cin.putback(ch1); cin >> ch2; a. W b. X ANS: A c. Y d. Z PTS: 1 REF: 135-136 15. Suppose that ch1 and ch2 are char variables and the input is: WXYZ What is the value of ch2 after the following statements execute? cin >> ch1; ch2 = cin.peek(); cin >> ch2; a. W b. X ANS: B c. Y d. Z PTS: 1 REF: 135-136 16. In C++, the dot is an operator called the ____ operator. a. dot access c. data access b. member access d. member ANS: B PTS: 1 REF: 137 17. Suppose that x = 25.67, y = 356.876, and z = 7623.9674. What is the output of the following statements? cout << fixed << showpoint; cout << setprecision(2); cout << x << ' ' << y << ' ' << z << endl; a. 25.67 356.87 7623.96 b. 25.67 356.87 7623.97 ANS: C PTS: 1 c. 25.67 356.88 7623.97 d. 25.67 356.876 7623.967 REF: 143-145 18. Suppose that x = 55.68, y = 476.859, and z = 23.8216. What is the output of the following statements? cout << fixed << showpoint; cout << setprecision(3); cout << x << ' ' << y << ' ' << setprecision(2) << z << endl; a. 55.680 476.859 23.82 b. 55.690 476.860 23.82 ANS: A PTS: 1 c. 55.680 476.860 23.82 d. 55.680 476.859 23.821 REF: 143-145 19. Suppose that x = 1565.683, y = 85.78, and z = 123.982. What is the output of the following statements? cout << fixed << showpoint; cout << setprecision(3) << x << ' '; cout << setprecision(4) << y << ' ' << setprecision(2) << z << endl; a. 1565.683 85.8000 123.98 b. 1565.680 85.8000 123.98 ANS: C PTS: 1 c. 1565.683 85.7800 123.98 d. 1565.683 85.780 123.980 REF: 143-145 20. What is the output of the following statements? cout << setfill('*'); cout << "12345678901234567890" << endl cout << setw(5) << "18" << setw(7) << "Happy" << setw(8) << "Sleepy" << endl; a. 12345678901234567890 ***18 Happy Sleepy b. 12345678901234567890 ***18**Happy**Sleepy c. 12345678901234567890 ***18**Happy Sleepy d. 12345678901234567890 ***18**Happy Sleepy** ANS: B PTS: 1 REF: 149-150 21. What is the output of the following statements? cout << "123456789012345678901234567890" << endl cout << setfill('#') << setw(10) << "Mickey" << setfill(' ') << setw(10) << "Donald" << setfill('*') << setw(10) << "Goofy" << endl; a. 123456789012345678901234567890 ####Mickey Donald*****Goofy b. 123456789012345678901234567890 ####Mickey####Donald*****Goofy c. 123456789012345678901234567890 ####Mickey####Donald#####Goofy d. 23456789012345678901234567890 ****Mickey####Donald#####Goofy ANS: A PTS: 1 22. ____ is a parameterized stream manipulator. a. endl b. fixed ANS: D PTS: 1 REF: 149-150 c. scientific d. setfill REF: 153 23. Manipulators without parameters are part of the ____ header file. a. iostream c. ifstream d. pmanip b. iomanip ANS: A PTS: 1 REF: 153 24. Consider the following program segment. ifstream inFile; int x, y; //Line 1 //Line 2 ... //Line 3 inFile >> x >> y; //Line 4 Which of the following statements at Line 3 can be used to open the file progdata.dat and input data from this file into x and y at Line 4? a. inFile.open("progdata.dat"); b. inFile(open,"progdata.dat"); c. open.inFile("progdata.dat"); d. open(inFile,"progdata.dat"); ANS: A PTS: 1 REF: 167-169 25. Suppose that outFile is an ofstream variable and output is to be stored in the file outputData.out. Which of the following statements opens the file outputData.out and associates outFile to the output file? a. outFile("outputData.out"); b. outFile.open("outputData.out"); c. open(outFile,"outputData.out"); d. open.outFile("outputData.out"); ANS: B PTS: 1 REF: 167-169 COMPLETION 1. C++ comes with a wealth of functions, called ____________________ functions, that are written by other programmers. ANS: predefined pre defined pre-defined PTS: 1 REF: 129 2. In the C++ statement, cin.get(u); u must be a variable of type ____________________. ANS: char PTS: 1 REF: 132 3. The function ____________________ returns the next character in the input stream; it does not remove the character from the input stream. ANS: peek PTS: 1 REF: 135 4. The stream function ____________________ lets you put the last character extracted from the input stream by the get function back into the input stream. ANS: putback PTS: 1 REF: 135 5. The functions get, ignore, and so on are members of the data type ____________________. ANS: istream PTS: 1 REF: 137 6. C++ has a special name for the data types istream and ostream. They are called ____________________. ANS: classes PTS: 1 REF: 137 7. cin is called a(n) ____________________ object. ANS: istream PTS: 1 REF: 137 8. In C++, the dot is an operator called the ____________________operator. ANS: member access PTS: 1 REF: 137 9. To use the manipulator setprecision, the program must include the header file ____________________. ANS: iomanip PTS: 1 REF: 143 10. On some compilers, the statements cin >> fixed; and cin >> scientific; might not work. In this case, you can use the statement ____________________ in place of cin >> fixed;. ANS: cin.setf(ios::fixed); PTS: 1 REF: 143 11. The manipulator ____________________ is used to output the value of an expression in a specific number of columns. ANS: setw PTS: 1 REF: 147 12. You can disable the manipulator left by using the stream function ____________________. ANS: unsetf PTS: 1 REF: 151 13. On some compilers, the statements cin >> left; and cin >> right; might not work. In this case, you can use the statement ____________________ in place of cin >> left;. ANS: cin.setf(ios::left); PTS: 1 REF: 152 14. To use a parameterized stream manipulator in a program, you must include the header file ____________________. ANS: iomanip PTS: 1 REF: 153 15. C++ provides a header file called ____________________, which is used for file I/O. ANS: fstream PTS: 1 REF: 158