Practice midterm solutions

23 October 2013

1. The following program just uses variables. What does the program output?

#include <iostream>
using namespace std;
int main()
{
    int lisa = 5;
    double bart = 5 / 2.0;
    lisa++;
    int maggie = lisa / 2;
    maggie *= 3;
    cout << lisa << ", " << bart << ", " << maggie << "\n";
    return 0;
}

Output:

6, 2.5, 9

2. The following program uses conditions. What does the program output?

#include <iostream>
using namespace std;
int main()
{
    int bilbo = 9;
    int frodo = 3;
    if(bilbo % 2 == 0)
    {
        frodo *= 2;
        bilbo++;
    }
    else
    {
        bilbo--;
        frodo *= 4;
    }
    cout << bilbo << ", " << frodo << "\n";
    return 0;
}

Output:

8, 12

3. The following program uses a switch. What does the program output?

#include <iostream>
using namespace std;
int main()
{
    int bill = 9;
    int ted = bill - 4;
    switch(ted)
    {
    case 3: cout << "ant ";
    case 2: cout << "bee "; break;
    case 5: cout << "cat ";
    case 4: cout << "dog "; break;
    default: cout << "eel ";
    }
    cout << "\n";
    return 0;
}

Output:

cat dog 

4. The following program uses a while loop. What does the program output?

#include <iostream>
using namespace std;
int main()
{
    int tux = 29;
    while(tux > 0)
    {
        cout << (tux % 3);
        tux /= 3; // Hint: INTEGER division
    }
    cout << "\n";
    return 0;
}

Output:

2001

5. The following program uses a for loop. What does the program output?

#include <iostream>
using namespace std;
int main()
{
    for(int i = 1; i < 40; i *= 3)
    {
        cout << i << "\n";
    }
    return 0;
}

Output:

1
3
9
27

6. The following program uses nested if/else statements. Given the values of baz and tar as inputs, what does the program output?

• baz = 6; tar = 3; Output: Belgium Chile France
• baz = 3; tar = 6; Output: Denmark France
• baz = 6; tar = 9; Output: Chile France
• baz = 9; tar = 6; Output: Austria Belgium Chile France
• baz = 3; tar = 4; Output: Denmark Egypt France

#include <iostream>
using namespace std;
int main()
{
    int baz, tar;
    cin >> baz >> tar; // Receives values as shown above
    if(baz > 4)
    {
        if(baz > 8)
        {
            cout << "Austria ";
        }
        if(tar < 8)
        {
            cout << "Belgium ";
        }
        cout << "Chile ";
    }
    else
    {
        cout << "Denmark ";
        if(tar < 6)
        {
            cout << "Egypt ";
        }
    }
    cout << "France\n";
    return 0;
}

7. The following program uses nested loops. What does the program output?

#include <iostream>
using namespace std;
int main()
{
    for(int i = 1; i < 4; i++)
    {
        for(int j = i; j < 5; j++)
        {
            cout << j << " ";
        }
        cout << "\n";
    }
    return 0;
}

Output:

1 2 3 4 
2 3 4 
3 4 

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