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Javascript | Loops
Question 1
Can the initialization statement in a for loop declare multiple variables?
Yes, like for (let i = 0, j = 10; i < 5; i++) {}
No, only one variable can be declared.
Only if they are related to each other.
It will cause a syntax error.
Question 2
What will be the output of the following code?
let arr = [1, 2, 3]; for (let i in arr) { console.log(i); }
0, 1, 2
1, 2, 3
"0", "1", "2"
"1", "2", "3"
Question 3
Which of the following code snippets will result in an infinite loop?
JavaScript let i = 10; while (i > 0) { console.log(i); i--; }
JavaScript let i = 5; while (i > 0) { console.log(i); }
JavaScript let i = 5; do { console.log(i); i--; } while (i >= 0);
JavaScript let i = 0; while (i < 5) { i++; console.log(i); }
Question 4
What will happen if you use for (let i = 0; i <= arr.length; i++) to loop through an array?
It will correctly loop through all elements.
It will try to access arr[arr.length], which is undefined.
It will skip the last element.
It will cause a syntax error.
Question 5
What will be the output of the following code?
let num = 10; while (num > 0); { num -= 2; console.log(num); }
10 8 6 4 2 0
8 6 4 2 0
Error
Infinite loop
Question 6
What will be the output of the following code?
let i = 0; while (i++ < 3) { console.log(i); }
0 1 2
1 2 3
0 1 2 3
1 2
Question 7
What will be the value of i after the following loop?
for (let i = 0; i < 3; i++) {} console.log(i);
0
2
3
ReferenceError: i is not defined
Question 8
What is the difference between for...in and for...of when used with arrays?
for...in gives indices, for...of gives values
for...in gives values, for...of gives indices
Both give values
Both give indices
Question 9
How many times will be the while condition executed?
let i = 0; while (i < 5) { i++; } console.log(i);
5
4
6
Infinity
Question 10
In a for loop, if the initialization is omitted, what happens?
let i = 10; for ( ; i < 15; i++) { console.log(i); }
It uses the current value of i
It starts from 0
Syntax error
It doesn't run
There are 10 questions to complete.