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Questions

  1. Rewrite the following if statements into a single if ... then ... else statement:

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    if (age < 18)
    ageCategory = "Junior";
if (age >= 18)
    ageCategory = "Senior";

  2. What is the output from the following code?

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    int sum = 17;
if (sum < 20)
    Console.Write("Under ");
else
    Console.Write("Over ");
Console.WriteLine("the limit");

  3. Write an appropriate selection statement/construct to do the following:

    • If an integer variable currentNum is odd, change its value so it is now \(3\) times the currentNum + \(1\), otherwise change its value so that it is now half the value of currentNum (rounded down when currentNum is odd)
    • If an integer variable n has the value \(1\), read in double values for X and Y, calculate and print their sum
    • Assign a value to a double variable cost depending on the integer variable distance as in the following table:
Distance Cost
0 through 100 5.00
More than 100 but not more than 500 8.00
More than 500 but less then 1,000 10.00
1,000 or more 12.00

Additional Exercises

  1. Write an if-statement that takes two integer variables and exchanges their values if the first one is greater than the second one.
  2. Write a program that asks for a digit (0-9), and depending on the input, shows the digit as a word (in English) using a switch statement.
  3. A year is a leap year if it is divisible by 4, unless it is a century year, in which case it is only a leap year if it is divisible by 400 (e.g. 2000 is a leap year, but 1900 was not). Design and write a program to accept a year and output a message indicating if it is a leap year.

  4. (something to stretch the Maths muscles ...) Write a program that gets the coefficients \(a\), \(b\) and \(c\) of a quadratic equation: \(ax^{2} + bx + c\), calculates and prints its real roots (if they exist).

    Tip

    A quadratic equation may have one or two real roots or no real roots at all. In order to calculate the real roots of a given quadratic equation, we first calculate the discriminant (\(D\)) by the formula: \(D = b^{2} - 4ac\). If the discriminant (\(D\)) is zero, then the quadratic equation has one double real root and it is calculated by the formula: \(x_{1,2} = \frac{-b}{2a}\). If the value of the discriminant is positive, then the equation has two distinct real roots, which are calculated by the formula: \(x_{1,2} = \frac{-b \pm \sqrt{b^2-4ac}}{2a}\). If the discriminant is negative, the quadratic equation has no real roots). Quadratic equations may have 0, 1 or 2 real roots. The Math namespace has a square root method: Math.Sqrt().

  5. READ and DO the tutorial on iteration