For Loops
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. Does a for loop have three parts separated by semicolons?
2. Must 'for' be written in lowercase?
3. Does i++ increase i by 1 after each pass?
4. Can a for loop count down using i--?
5. Are the three parts of a for loop separated by commas?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1for (let i = 1; i <= 3; i++) { ... } | AWrong - the parts of a for loop use semicolons, not commas | |
| 2for (let j = 5; j > 0; j--) { ... } | Bi++ | |
| 3Sets the loop counter's starting value | CRuns the block 3 times, with i going from 1 to 3 | |
| 4Increases i by 1 after each pass through the loop | Dlet i = 1 | |
| 5for let i = 1; i <= 3; i++ { ... } | ECounts down from 5 to 1, decreasing j each pass | |
| 6for (let i = 1, i <= 3; i++) { ... } | FWrong - the loop header needs parentheses |
C
Definitions
for
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
___ (let i = 1; i <= 3; i++) {
2.
for (let i = 1; i __ 3; i++) {
3.
for (let i = 1; i <= 3; i__) {
4.
for (let j = 5; j > 0; j__) {
5.
for (___ k = 0; k < 4; k++) {
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
For (let i = 1; i <= 3; i++) {
B
console.log(i);
C
}
Question 2
A
console.log(i);
B
for let i = 1; i <= 3; i++ {
C
}
Question 3
A
let total = 0;
B
console.log(total);
C
for (let i = 1, i <= 3; i++) {
Question 4
A
console.log(i);
B
console.log(x);
C
console.log(y);
D
for (let i = 1; i <= 3; i++) [
Question 5
A
for (let i = 0; i < 5; i++) {
B
console.log(i)
C
}
Answer Key
For Loops
Section A: Quick Questions
Q1
A — Yes
Q2
B — Yes
Q3
B — Yes
Q4
A — Yes
Q5
A — No
Section B: Match the Pairs
Q1
for (let i = 1; i <= 3; i++) { ... } → Runs the block 3 times, with i going from 1 to 3
Q2
for (let j = 5; j > 0; j--) { ... } → Counts down from 5 to 1, decreasing j each pass
Q3
Sets the loop counter's starting value → let i = 1
Q4
Increases i by 1 after each pass through the loop → i++
Q5
for let i = 1; i <= 3; i++ { ... } → Wrong - the loop header needs parentheses
Q6
for (let i = 1, i <= 3; i++) { ... } → Wrong - the parts of a for loop use semicolons, not commas
Section C: Definitions
Q1
for — Repeats a block of code a set number of times, using an initializer, condition, and update expression.Section D: Fill in the Blanks
Q1
for (let i = 1; i <= 3; i++) {Q2
for (let i = 1; i <= 3; i++) {Q3
for (let i = 1; i <= 3; i++) {Q4
for (let j = 5; j > 0; j--) {Q5
for (let k = 0; k < 4; k++) {Section E: Spot the Error
Q1
A — 'for' must be lowercase - a capital F causes an error.
Q2
B — The loop header needs parentheses: for (...).
Q3
C — The three parts of a for loop are separated by semicolons, not commas.
Q4
D — Code blocks use curly braces {}, not square brackets [].
Q5
B — This line is missing a semicolon, but that's not required in JS.