CSCI 102 – Midterm 1 Practice

Questions

Q1:

What is the value of c after the following lines execute?

   int a = 5;
   int c = a;
   a -= 3;

c = 5
c = 3
c = 2
c = -1

Q2:

What is the value of c after the following lines execute?

   int a = 5;
   int b = a;
   b + 1;
   int c = b;

c = 1
c = 5
c = 6

Q3:

What is the value of b after the following lines execute?

   int a = -2;
   int b = a; 
   int c = b + 7; 
   a++; 
   b + =a; 
   b * =c; 
   b = -b % c; 

b = 5
b = -5
b = 0
b = 3

Q4:

What are the values of variables a, b, and c at the end of the program?

#include <iostream>
using namespace std;
int main()
{
	int a = 5;
	int b = a;
	int c = 3;

	a = 25 % c;
	b = b * (1 / b);
	c++;
	return 0;
}

Q5:

What is output to the screen by this program?

#include <iostream>
using namespace std;
int main()
{
	int a, b,c;
    a=5;
    b=a + 2 * a;
    c=b*a+b/a;

    cout << c << endl;
	c%=a
	cout << c << endl;

	return 0;
}

Q6:

Which of these will compile?

int x; cin >> x;
int x = 0; cin >> x;
int x; cin << x;
cin >> x; int x;

Q7:

The user types the following text as input to the program:

97 is 'a'

What are the values of x, y, and z at the end of the program?

#include <iostream>
using namespace std;

int main() {
    char c;
    string s1;
    string s2;

    cin >> c >> s1 >> s2;

    cout << "c: " << c << endl;
    cout << "s1: " << s1 << endl;
    cout << "s2: " << s2 << endl;

    return 0;
}

Q8:

Which line of code will output 12? Assume <iomanip> is included.

cout << 1 2 << endl;
cout << setprecision(0) << fixed << 12.5 << endl;
cout << setw(2) << 1 << setw(2) << 2 << endl;

Q9:

What will the following code output?

#include <iostream>
using namespace std;

int main()
{
    double a = 0.5;
    char b = ',';
    bool c = false;
    string d = "Hello";

    for(int i = 0; i < 3; i++){
        cout << a + i << b << ' ';
    }
    cout << a+3 << endl;
    cout << boolalpha << c << 'd' << endl;
}

Q10:

What will be stored in x after the following expression is evaluated:

double x = ((int)4.75 % 3) % 5; 

The code will not compile because modulo may only be used with integers
The code will not compile because you cannot assign the result of a modulo operation to a double
x = 2.0
x = 1.0
x = 0.0

Q11:

What will be stored in the variable y after the following line of code is executed?

int y = 3.0 / (2 % 100) * (25.0 + 8) + 8;

56
56.5
57
57.5
You will get an error message.

Q12:

What will be stored in a,b, and c at the end of this code snippet:

int a = 11;
int b = 3;
int c = 10;
double d = 3.99;

a = (a + b) / (double)b;
b = c / (int)d;
c = (double)(b * 1.0) / 4.0;

Q13:

What will be printed to the terminal in the following program?

double a = 3.5;
double b = 10.0;
int x = 4;
int y = b/x;


cout << a + b << endl;
cout << b / x << endl;
cout << y << endl;
cout << a * b * y << endl;

Q14:

What will the following code output?

int a = 0;
int b = 2;
double c = 4.0;
double d = 4.0;

a++;
b += 3;
c = a / (int)d + a / c;
d = (a * 1.0) / (int)d + a / b;

cout << a << " " << b << " " << c << " " << d << endl;

Q15:

What will be printed as a result of this code?

int w = 5;
int x = 3;
double y = 4.0;
double z = 2.5;

int a = x + y / z - w;
int b = (double) w / 2 + 3.5;
y = 5.0 * b - a + 0.25;

cout << a << " " << b << " " << y << endl;

Q16:

True or False: You should avoid calling cin and cout within the body of a for loop, as it may upset the loop counter behavior.

Q17:

True or False: ‘for’ loops check the condition after axecuting the body of the loop at least once and then repeat the body if the condition is true.

Q18:

True or False: The loop below is an infinite loop (will run forever)?

for(int i = 1; i < 10; i += 2){
    cout << i << endl;
}

Q19:

What will be the output for the following program?

#include <iostream>
using namespace std;

int main()
{
        int a = 2;
        int b = -1;
        for (b = 5; b > 0; b--){
            a *= b;
        }

        cout << a;
        return 0;
}

Q20:

Which of the following are necessary for a function prototype? (Select all that apply.)

Number and type of argument/parameters
Value to be returned
Type to be returned
Function name

Q21:

What is the output of the code below?

int f1 (int x, double y)
{
    if (x/(int)y > 0)
        return x/y;
    else
        cout << x * y << endl;
        return x * y;
}

int main()
{
    int x = 5;
    double y = 2.0;
    x = f1(x, y);
    y = (double)f1(x, 3.5);
    cout << (y-2)/2 << '\n';
    return 0;
}

Q22:

Based on the structure of the code and allowing any possible value of the variable a, what are all the actions that could execute?

if (a < 5) 
{		
    if(a >= 2)
    {
        // action 1
    }
    else if(a == 2)
    {
        // action 2
    }
    // action 3
}
else if(a < 10)
{
    if(a <= 5)
    {
        // action 4
    }
    // action 5
}

1, 3, 4, 5
1, 2, 5
1, 2, 3, 4
1, 3, 5
None of the above

Q23:

Which of the following is true?

We can have more than one else blocks
We can have only one else if block
In an if condition, the compiler will interpret any non-zero result of the condition to mean true
if blocks must be executed at least once

Q24:

Which blocks are executed in the code below?

bool skyBlue = true;
bool threeWheat = true;
bool bread = true;
char gameMode = 'C';

if(threeWheat == bread){
	// block 1
}
else if(gameMode == 'C'){
	// block 2
}
else if(threeWheat == bread){
	// block 3
}
else{
	// block 4
}

if(skyBlue == bread){
	// block 5
}
if(threeWheat == skyBlue){
	// block 6
}
else if(gameMode != 'B'){
	// block 7
}
else{
	// block 8
}

1,2,3,5,6
1,5
1,5,6
1,5,6,7

Q25:

What will the following code output?

int a = 0;
int b = 1;
int c = 2;

b = c * c;
if(a < b && b == 4)
{
    c = 10;
    if(c - a > b + 4)
    {
        c = a;
    }
    else
    {
        c = b + a;
    }
    b = a - b + c;
}
else
{
    b += 9 + c;
}
a = c + 3;
if(a < b || b > 1)
{
    a += b + c;
}
cout << "a = " << a << "; b = " << b << "; c = " << c << ";" << endl;

a = 7; b = 0; c = 4;
a = 3; b = -4; c = 0;
a = -1; b = -4; c = 0;
a = 7; b = 4; c = 0;

Q26:

Each student has an ID. The ID number can be decoded to get some basic information of the student, including legacy, year in school, and major. Assume the user inputs an id of 140557.

What will the program print for that input?

int id; 
cout << "Please enter the student ID: ";
cin >> id;

if(id % 10 % 2) {
    cout << "Legacy" << endl;    
}
else {
    cout << "Non-legacy" << endl;    
}

int a = id / 1000;
int b = id % 1000;

if(a < 300 || b > 200) {
    cout << "Viterbi School of Engineering" << endl;
    
    if(a + b < 500) {
        cout << "CSCI Major" << endl;  
    }
    else if(a - b < 0) {
        cout << "CSBA Major" << endl;    
    }
    else {
        cout << "CECS Major" << endl;    
    }
}
else {
    cout << "Marshall School of Business" << endl;
    
    if(a + b > 500) {
        cout << "BUAD Major" << endl;  
    }
    
}

id /= 100;
int c = id % 10;

if(!(c % 3)) {
    cout << "Freshmen" << endl;    
}
else if (c % 5 == 0) {
    cout << "Sophomore" << endl;    
}
else if (c / 4 >= 3) {
    cout << "Junior" << endl;    
}
else {
    cout << "Senior" << endl;    
}

Q27:

Understand the code below and then answer the following questions:

bool feelingSick = 1;
bool goneToKeck = false;
int wonderingIfCovid = 1;
bool goToSchool = false;
if(feelingSick){
	wonderingIfCovid++;
	if(!goToSchool){
		if(goneToKeck){
			cout << "waiting for test results" << endl;
		}
		else if(!goneToKeck){
			wonderingIfCovid += 2;
			cout << "get tests done" << endl;
			goneToKeck = true;
			if(!feelingSick){
				goToSchool = true;
			}
			else if(wonderingIfCovid == 2){
				cout << "it's probably something else" << endl;
				goToSchool = false;
			}
			else{
				cout << "test results are completed and consequently lost" << endl;
				if(feelingSick && wonderingIfCovid >= 5){
					cout << "I'm in danger" << endl;
				}
				else if(feelingSick && wonderingIfCovid <= 2){
					goToSchool = false;
				}
				else{
					cout << "The director of Keck calls and apologizes" << endl;
				}
			}

		}
		else{
			cout << "The director of Keck calls and apologizes" << endl;
		}

		goneToKeck = true;
		wonderingIfCovid -= 3;
	}
}
else{
	wonderingIfCovid--;
	goToSchool = true;
	if(goToSchool){
		cout << "TA Megan's puns in lab encouraged me to attend" << endl; 
	}
}

Yes/No: Does the director of Keck ever call and apologize?
What is the value of wonderingIfCovid at the program’s termination?
Yes/No: Is the print statement "it's probably something else" reached?

Q28:

Which of the following returns false if x is set to 10?

x >= 0
x != 5
x > 10
x <= 100

Q29:

What does the following program output?

#include <iostream>
using namespace std;
int main()
{
	int code = 25;
	if((code / 2) > 12)
	{
		cout << "A" << endl;
	}
	else if((code == 25) && (code < 25))
	{
		cout << "B" << endl;
	}
	else if(!(code > 10) || (code != 50))
	{ 
		cout << "C" << endl;
	}
	else
	{
		cout << "I have no idea" << endl;
	}

	return 0;
}

Q30:

What does the following program output?

#include <iostream>
using namespace std;
int main()
{
   bool A = 1 > 1;
   bool B = 0 <= 3;
   if (A || B) {
       cout << "1" << endl;
   }
   if (A && B) {
       cout << "2" << endl;
   }
   if (!A && B) {
       cout << "3" << endl;
   }
   return 0;
}

Q31:

True/False: The code below will run forever.

while (1) {
    cout << "hello 102";
    int a = 0;
    if (a != 0) break;
    ++a;
}

Q32:

Is this valid syntax for a while loop condition?

	int x = 0;
	int y = 1;
	while (max(x,y)) 
	{
		cout << "I love CS102!" << endl;
	}

Yes, the compiler will interpret the result of the function as a Boolean.
Yes, the compiler interprets the condition as false and never enters the loop.
No, the compiler will not be able to interpret the function as a Boolean.
No, max(x,y) is not a valid function and will not compile.

Q33:

How many times will Here be printed by this loop execute?

int i = 0;
while(i < 10)
{
  cout << "Here" << endl;
  if(i % 2 == 0)
  {
     i++;
  }
  if(i == 5)
  {
    break;
  }
  i++;
}

3
10
5
the loop is infinite

Q34:

Given an example of inputs that will produce the output n = 8

#include <iostream>
using namespace std;
int main()
{
    int i=0, j, x, y, n = 0;
    cout << "Input two integers:" << endl;
    cin >> x >> y;
    if (y < 11)
    {
      while(i<=x)
      {
          for (j = 0; j<=y; j++)
        {
          if(i >= 5 || j >= 10)
          {
            break;
          }
          if(i%2 == 0 && j%3 == 0)
          {
              n+=1;
          }
        }
        i++;
      }
    }
    cout << "n = "<< n <<endl;
    return 0; 
}

Q35:

What will be the value of x after the following code is executed?

int x = 0;
int n = 3;
while (n > 1)
{
    if (n % 2 == 0)
    {
        n = n / 2;
    }
    else
    {
        n = 3 * n + 1;
    }
    x++;
}

Q36:

What will be printed by this snippet of code?

int a = 0, b = 1;
while (a || b) {
    a *= b;
    b *= a;
    cout << a << ", " << b << endl;
}

Q37:

What initial values for num_1 and num_2 would cause Congratulations to be printed on the last line of the following code snippet?

int num_1 = ??;
int num_2 = ??;
int a = 100;
int count = 0;
while (num_1 < num_2 || num_2 > a)
{
    num_1 += num_1 % num_2;
    num_2--;
    count++;
}
if(count == 3) {
    cout << "Congratulations" << endl;
}

num_1 = 101, num_2 = 99
num_1 = 70, num_2 = 105
num_1 = 95, num_2 = 103
num_1 = 10, num_2 = 20

Q38:

How many times will “hello world” be printed in the following code snippet?

int a = 0;
int b = 3;
for (int c = 9; a < 5 && c >= 0; a++)
{
    c -= b;
    cout << "hello world!" << endl;
}

Answers

A1: A
A2: B
A3: C
A4: a=1, b=0, c=4
A5:
```
  78
  3
```
A6: A,B
A7:
```
  c: 9
  s1: 7
  s2: is
```
A8: B
- Explanation:
  - A) Will not compile due to the whitespace in between the two integers.
  - B) setprecision(0) and fixed set the precision of the subsequent decimal portion to 0, removing the .5 and outputting 12 and
  - C) setw(2) adds a space before and between the 1 and the 2, resulting in ` 1 2, which is not 12`.
A9:
```
  0.5, 1.5, 2.5, 3.5
  falsed
```
A10: D) x = 1.0
A11: C
A12:
```
  a = 4
  b = 3
  c = 0
```
A13:
```
  13.5
  2.5
  2
  70
```
A14: 1 5 0.25 0.25
A15: 0 6 30.25
A16: False
A17: False
A18: False
A19: 240
A20: A, C, and D
A21:
```
  7
  2.5
```
A22: E) None of the above
A23: C
A24: C) 1,5,6
A25: B) a = 3; b = -4; c = 0;

A26:

  Legacy
  Viterbi School of Engineering
  CSBA Major
  Sophomore

A27: Yes, 1, No
A28: C
A29: C
A30:
```
  1
  3
```
A31: True
A32: A
A33: A
A34: x = 2 or 3 along with y = 9 or 10.
A35: 7
A36: 0, 0
A37: C
A38: B