Exam 1

Question 1

1. Assume a string object has been defined as follows:
   string description;

Write a cin statement that reads in one word to description.

Answer 1

cin >> description;

Question 2

Assume a string object has been defined as follows:
string description;

Write a statement that reads into description multiple words separated by blanks.

Answer 2

getline(cin , description);

Question 3

Assume the following variables are defined:

int age; 
double pay; 
char section; 

Write a single cin statement that will read input into each of these variables.

Answer 3

cin >> age >> pay >> section;

Question 4

What header files must be included in the following program?

int main() { 
double amount = 89.7; 
cout << fixed << showpoint << setprecision(1); cout << setw(8) << amount << endl; return 0; 
} 

Answer 4

#include <iostream>
 // cin and cout 
#include <iomanip> 
// setw, showpoint, fixed and setprecision 

Question 5

Write a statement that defines a constant variable named RATE whose value is set to 0.12

Answer 5

const double RATE = 0.12;

Question 6

What header file must be included to perform mathematical functions like sqrt?

Answer 6

#include <cmath>

Question 7

What header file must be included to use cin and cout?

Answer 7

#include <iostream>

Question 8

What header file must be included to use stream manipluators like setprecision?

Answer 8

#include <iomanip>

Question 9

What header file must be included to use random numbers rand() and srand()?

Answer 9

#include <cstdlib>

Question 10

What header file must be included to use time for random generator?

Answer 10

#include <ctime>

Question 11

Find the Errors

Cout << "Enter a number: "; 
Cin << number1; 
Cout << "Enter another number: "; 
Cin << number2; 
number1 + number2 = sum; 
Cout "The sum of the two numbers is " << sum;

Answer 11

**c**out << "Enter a number: "; 
**c**in **>>** number1; 
**c**out << "Enter another number: "; 
**c**in >> number2; 
**sum =** number1 + number2; 
**c**out **<<** "The sum of the two numbers is " << sum ; 

Question 12

Find the errors:

const int number1, number2, product; 
cout << "Enter two numbers and I will multiply\n"; 
cout << "them for you.\n"; 
cin >> number1, number2; 
product = number1 * number2; 
cout << “product is” << “product”; 

Answer 12

int number1, number2, product; // **remove const keyword **
cin >> number1** >> **number2; 
cout << “product is “ << **product**; //no double quotes around the variable 

Question 13

Find the Error
The following program contains many syntax errors. Locate as many as you can.

2. #include iostream 
3. using namespace std; 
4. 
5. int main(); 
6. } 
7. int a, b, c \\ Define 3 integers 
8. a = 3 
9. b = 4 
10. c = a + b 
11. Cout >> "The value of c is " >> C; 
12. return 0; 
13. { 

Answer 13

2. #include **<iostream>** 
3. using namespace std; 
4. 
5. int main() //no semicolon after main() 
6. **{** //open 
7. int a, b, c**;** //Define 3 integers 
8. a = 3**; **
9. b = 4**; **
10. c = a + b**;** 
11. **c**out**<<** "The value of c is " **<<** **c**; 
12. return 0; 
13. } 

Question 14

What will the following program segment display?

int unus, duo, tres; 
unus = duo = tres = 5; 
unus += 4; 
duo *= 2; 
tres −= 4; 
unus /= 3; 
duo += tres; 
cout << unus << endl << duo << endl << tres << endl; 

Answer 14

3 11 1

Question 15

Convert the following pseudocode to C++ code. (Don’t need to write the whole program.)

Store 172.5 in the force variable.
Store 27.5 in the area variable.
Divide area by force and store the result in the pressure variable.
Display the contents of the pressure variable.

Answer 15

double force, area, pressure; 
force = 172.5; 
area = 27.5; 
pressure = area / force; 
cout << “ the pressure is “ << pressure;

Question 16

What is the exact output when the following code is executed?

int price = 100; 
if (price = 50) 
    cout << "The total price is 50." << endl; 
else 
    cout << "The total price is not 50." << endl; 

Answer 16

The total price is not 50.

Question 17

1. What is the exact output when the following code is executed?

int price = 100; 
if (price == 50) 
    cout << "The total price is 50." << endl; 
else 
    cout << "The total price is not 50." << endl; 

Answer 17

The total price is not 50.

Question 18

1. What is the exact output when the following code is executed?

int price = 100; 
if (price == 100) 
    cout << "The total price is 50." << endl; 
else 
    cout << "The total price is not 50." << endl; 

Answer 18

The total price is 50.

Question 19

Rewrite the following program. Use a switch statement instead of the if/else if statement.

#include <iostream> 
using namespace std; 
int main() { 
   int selection; 
   cout << "Which formula do you want to see?\n\n"; 
   cout << "1. Area of a circle\n"; 
   cout << "2. Area of a rectangle\n"; 
   cout << "3. Area of a cylinder\n"; 
   cout << "4. None of them!\n"; 
   cin >> selection; 
   if (selection == 1) 
      cout << "Pi times radius squared\n"; 
   else if (selection == 2) 
      cout << "Length times width\n"; 
   else if (selection == 3) 
      cout << "Pi times radius squared times height\n"; 
   else if (selection == 4) 
      cout << "Well okay then, good bye!\n"; 
   else 
      cout << "Not good with numbers, eh?\n";
   return 0; 
}

Answer 19

#include <iostream> 
using namespace std; 

int main() { 
   int selection; 
   cout << "Which formula do you want to see?\n\n"; 
   cout << "1. Area of a circle\n"; 
   cout << "2. Area of a rectangle\n"; 
   cout << "3. Area of a cylinder\n"; 
   cout << "4. None of them!\n"; 
   cin >> selection; 

   switch (selection) { 
      case 1: 
         cout << "Pi times radius squared\n"; 
         break; 
      case 2: 
         cout << "Length times width\n"; 
         break; 
      case 3: 
         cout << "Pi times radius squared times height\n"; 
         break; 
      case 4: 
         cout << "Well okay then, good bye!\n"; 
         break; 
      default: 
         cout << "Not good with numbers, eh?\n"; 
      } 

   return 0; 
}

Question 20

What will the following program display?

#include <iostream> 
using namespace std;

int main() { 
   const int UPPER = 8, LOWER = 2;  
   int num1, num2, num3 = 12, num4 = 3;  
   num1 = num3 > num4 ? UPPER : LOWER; 
   num2 = num4 > UPPER ? num3 : LOWER; 
   cout << num1 << " " << num2 << endl; return

Answer 20

8 2

Question 21

What is the exact result?

int credits = 9; 
if (credits < 16)  { 
   if (credits > 11) 
      cout << "You have enough courses."; 
   } else 
      cout << "Add another course."; 
cout << "Go register for courses."; 

Answer 21

Go register for courses.

Question 22

What is the exact result?

int credits =13; 
if (credits < 16) { 
   if (credits > 11) 
      cout << "You have enough courses."; 
}
else { 
    cout << "Add another course."; 
cout << "Go register for courses."; 
}

Answer 22

You have enough courses

Question 23

Rewrite the following as an exactly equivalent do …while statement:

for ( int numComputers = 1; numComputers < 10; numComputers++)
cout << “Computer #” << numComputers << endl;

Answer 23

1```
int numComputers = 0;

do {
cout &laquo_space;“Computer #” &laquo_space;numComputers &laquo_space;endl;
numComputers++;
} while(numComputers < 10);
~~~

Question 24

Given int variables k and total that have already been declared, use a do..while loop to compute the sum of the squares of the first 50 counting numbers, and store this value in total. Thus your code should put 11 + 22 + 33 +… + 4949 + 50*50 into total. Use no variables other than k and total.

Answer 24

total=0;
k=1;

do {
total+=k*k;
k++;
} while(k<=50);

Question 25

Write a cout statment so that the variable population is displayed in a field of 12 spaces, left-justified, in fixed-point notation, with a precision of 8 decimal places. The decimal point should always be displayed.

Answer 25

`cout << setw(12) << left << fixed << showpoint << setprecision(8) << population;`

Question 26

Write the code to type cast an int to a double.

Answer 26

`static_cast(intVar);`

Question 27

modulus operator

Answer 27

`%` returns the remainder after division. example: `8%2 = 0` `8%3 = 2` good for use in checking odd or even ``` if (num % 2 = 0) { // even } else { // odd } ```

Question 28

Write code that reads the first character of the next line into `char c;`

Answer 28

``` char c; cin.ignore(100, ‘\n’); c = cin.get(); ```

Question 29

Write a cin statment for `string name;` to take in one word.

Answer 29

``` string name; cin >> name; ```

Question 30

Write a cin statment for `string name;` to take in multiple words.

Answer 30

``` string name; getline(cin, name); ```