# “Loops” memo. Part 1

## Loop for

### Syntax

```
for (var i = 0; i < 10; i++) {
// repeated commands
}
```

`var i = 0;`

preparatory part, the initial value for the counter. Set with `var`

, as an ordinary variable.

`i < 10;`

checking part. If the condition returns `true`

, the loop completes one more iteration, otherwise the loop stops.

`i++`

complementary part, launched at each iteration, after executing the code from the body of the loop. Changes counter value.

### Accumulation of values in a loop:

```
var sum = 0;
for (var i = 1; i <= 5; i++) {
sum += 2;
console.log(sum);
}
```

The program will log:

```
LOG: 2 (number)
LOG: 4 (number)
LOG: 6 (number)
LOG: 8 (number)
LOG: 10 (number)
```

### Checks in the loop body

```
var sum = 0;
for (var i = 1; i <= 5; i++) {
if (i > 2) {
sum += 1;
}
}
```

## Searching for an even number

The `%`

operator or the “remainder in division” returns the remainder in division.

```
10 % 5; // Returns 0
12 % 5; // Returns 2
7 % 3; // Returns 1
5.5 % 2; // Returns 1.5
```

If the remainder in division of the number by `2`

equals `0`

, the number is even, otherwise it is odd.

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