The loop for
allows you to repeat
some code a specified number of times.
Here is its syntax:
for ( initial commands; termination condition; commands after iteration ) {
loop body
}
The initial commands are what will be executed
before the start of the loop. They will be
executed only once. Usually, the initial values
of the counters are placed there,
for example: i = 0
.
The condition of the loop termination is a
condition under which the loop will spin,
while it is true , for example:
i <= 10
.
The commands after the loop iteration are
the commands that will be executed each
time the loop iteration ends. Usually
counters are increased there,
for example: i++
.
Let's use the loop for
to print
successively the numbers
from 1
to 9
:
for (let i = 1; i <= 9; i++) {
console.log(i); // shows 1, 2... 9
}
And now we will increase the counter not
by 1
, but by 2
:
for (let i = 1; i <= 9; i += 2) {
console.log(i); // shows 1, 3, 5...
}
You can do a countdown:
for (let i = 10; i > 0; i--) {
console.log(i); // shows 10, 9, 8...
}
Use the loop for
to print the
numbers from 1
to 100
to the console.
Use the for
loop to print the
numbers from 11
to 33
to the console.
Use the for
loop to output even
numbers between 0
and
100
to the console.
Use the for
loop to output odd
numbers in the range from 1
to 99
to the console.
Use the loop for
to print the
numbers from 100
to 0
to the console.