CSCI 40 Midterm

Variable arithmetic & output basics

100

What does the 'cout' statement do in c++?

it prints stuff out

200

the output of the following code:

    int x = 99;

    x /= 2;

    cout << x % 5;

4

300

what is 7 in binary?

0111

400

Which line(s) of code give an error?

    double pi = 3.14;

    circleRadius = 5;

    int perimeter = 2(pi * circleRadius);

    cout << perimeter;

circleRadius = 5;

int perimeter = 2(pi * circleRadius);

500

the output of the following code

    int x = 10;

    x++;

    cout << (sqrt(4+x/20));

2

Branches

100

What is the final value of numItems?

bonusVal = 10;
numItems = 1;
if (bonusVal == 10) {
   numItems = numItems + 3;
}

4

200

Is x =< y a valid expression?

no

300

What is y's ending value if the input is 15?
int x;
int y = 0;
cin >> x;
if (x = 20) {
   y = 3;
}

3

400

If the input sets int x with 5 and int y with 7, what is the ending value of z? z is declared as a boolean.

z = (x > y);

false

500

the final value of y

int x = 6;
int y = 8;
if (x < 10) {
   if (y < 5) y = y + 1;
   else y = 7;}
else y = y + 10;

7

Important stuff to know

100

How do we check if a number is even?

% by 2

200

When should you use a while loop instead of a for loop?

When you don't know how many iterations there will be

300

What are all the rules for variable names (how do we know if they are valid identifiers)

be a sequence of letters (a-z, A-Z), underscores (_), and digits (0-9)

start with a letter or underscore

400

There are about 8 billion people on this planet, create a variable named humanPop that can hold this number

long long humanPop;

OR 

unsigned long long humanPop;

500

what is the output of the following code:

    double x = 0.1;

    double y = 0.2;

    if(x + y == 0.3)

        cout << "true" << endl;

    else

        cout << "false" << endl;

false

Loops

100

Which statement is used to immediately jump out of a loop and execute the next line of code?

Break

200

Which statement will end the current iteration of a loop and begins the next

Continue

300

Which type of loop always runs at least once?

do while loop

400

How many times will this loop run?

int x = 0;

for(int i = 0; i <= 10; i++){

   x++;

}

11

500

What is the missing line of code in the following program?

    int x = 0;

    int sum = 0;

    while(x < 10){

        sum += x;

    }

x++ (or any way to increment x)

Arrays & Vectors

100

Which function is used to append an element to the end of a vector?

push_back()

200

Declare an integer array with a size of 3

int arr[3];

300

Which of these is NOT a vector function

.pop_back()

.back()

.size()

.length()

.at()

.push_back()

.length()

400

Write a line of code to assign a variable x with the value of the last element of a vector named v

x = v.size()-1;

OR

x = v.back();

500

Write a program to print the elements of a vector of any size. The name of the vector is v

for(int i = 0; i < v.size(); i++) 

    cout << v.at(i);