Computer Science Programming Basics in Ruby

4.8 Exercises

1. Prompt the user for an integer and test if it’s even or odd. Consider using the way Ruby rounds operations on integers when appropriate. Save this program in a file called compare.rb.

2. Modify compare.rb so that it:

   1. Prompts the user for an integer between 5 and 10 (inclusive) and displays whether or not the input was correct. Implement this using an if/else statement.

   2. Prompts the user for an integer between 5 and 10 and then informs the user if the integer was below the range, in the range, or above the range. Implement this using a case statement.

3. Write a program that, given two points on a two-dimensional graph, outputs a message (string) if the line that connects them is horizontal or vertical, or if the slope is positive or negative.

4. Write a program to solve a system of two linear equations. A linear equation is a mathematical equation that describes a line through its slope (m) and its y-intercept (b), and it will take the form y = mx + b. Make sure to account for the cases where there is no solution or where there are an infinite number of solutions.

5. The unit pulse function, d[n], is very important in digital signal processing. This function is defined for integers only. It is equal to 1 when n is 0, and it is equal to 0 when n is any other integer. Write a program that prompts the user for an integer n, and returns the value d[n].

6. Prompt the user for integers x, y, and z. Implement the decision tree shown in Figure 4-6 based on the values using if statements. ...