Summary - Loops

Combine for, while and for-in to write a multiplication table.

Summary - Loops

In this group you learned for, while, do-while, for-in and break/continue. Now we will combine them to print a multiplication table.

The multiplication table is built by counting 1 to 5 with a for loop and writing 2 x i = (2*i) on each line. This structure combines repeated computation with formatted output.

Plan

We will build the multiplication table step by step: (1) count 1 to 5 with for (var i = 1; i <= 5; i++); (2) on each iteration write a line with print("2 x $i = ${2 * i}");; (3) interpolation embeds both i and 2 * i.

This structure is the skeleton of a real calendar or report app too. The loop + interpolation combo is the base of programs that produce screen output. Changing the number lets you build the 3-times or 4-times table easily.

Exercise Multiplication table

Build a for (var i = 1; i <= 5; i++) loop. In the body print each line with print("2 x $i = ${2 * i}");. The output must be 5 lines: 2 x 1 = 2, 2 x 2 = 4, 2 x 3 = 6, 2 x 4 = 8, 2 x 5 = 10 (one product per line).

Show example solution

for (var i = 1; i <= 5; i++) {
  print("2 x $i = ${2 * i}");
}

Test yourself

Which loop best fits the 2-times table (1-5)?
```
// multiplication table
```
- while
- for
- do-while
- if
Show answer

for — for is the best fit for a counted range.

Complete the for header

for (____) {
  print("2 x $i = ${2 * i}");
}

Show answer

for (var i = 1; i <= 5; i++) {
  print("2 x $i = ${2 * i}");
}

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