Exercise : for loop practice

• Copy and paste the following code into jGrasp.

  public class Triangle {
      public static void main(String[] args) {
          for (int line = 1; line <= 4; line++) {
              for (int stars = 1; stars <=  expression ; stars++) {
                  System.out.print("*");
              }
              System.out.println();
          }
      }
  }
  

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Exercise - fill in a table

We want to produce the following output:

*******
*****
***
*

Fill in the table below indicating how many stars appear on each line of output.

7

5

3

1

continued on the next slide...

Exercise - complete the expression

We need an expression for the number of stars on each line of this form:

multiplier * line + constant

• First pick a multiplier. Looking at the table, the line numbers go up by 1 each time, and the number of stars changes by how much each time? -2
• Now pick a constant. Look at the table to see how many stars are on line 1. Given your multiplier, what constant do you need to use in the expression to get that number of stars for line 1? 9
• Using your multiplier and constant, fill in the expression for this line of code in jGRASP:

  for (int stars = 1; stars <=  expression ; stars++) {
  

  Your program should now produce the correct output. You can verify with the Output Comparison Tool.