# C++ Array Size

## Get the Size of an Array

To get the size of an array, you can use the `sizeof()` operator:

### Example

int myNumbers[5] = {10, 20, 30, 40, 50};
cout << sizeof(myNumbers);

Result:

``` 20 ```
Try it Yourself »

Why did the result show `20` instead of ``` 5```, when the array contains 5 elements?

It is because the `sizeof()` operator returns the size of a type in bytes.

You learned from the Data Types chapter that an `int` type is usually 4 bytes, so from the example above, 4 x 5 (4 bytes x 5 elements) = 20 bytes.

To find out how many elements an array has, you have to divide the size of the array by the size of the data type it contains:

### Example

int myNumbers[5] = {10, 20, 30, 40, 50};
int getArrayLength = sizeof(myNumbers) / sizeof(int);
cout << getArrayLength;

Result:

``` 5 ```
Try it Yourself »

## Loop Through an Array with sizeof()

In the Arrays and Loops Chapter, we wrote the size of the array in the loop condition (```i < 5```). This is not ideal, since it will only work for arrays of a specified size.

However, by using the `sizeof()` approach from the example above, we can now make loops that work for arrays of any size, which is more sustainable.

Instead of writing:

int myNumbers[5] = {10, 20, 30, 40, 50};
for (int i = 0; i < 5; i++) {
cout << myNumbers[i] << "\n";
}

It is better to write:

### Example

int myNumbers[5] = {10, 20, 30, 40, 50};
for (int i = 0; i < sizeof(myNumbers) / sizeof(int); i++) {
cout << myNumbers[i] << "\n";
}
Try it Yourself »

Note that, in C++ version 11 (2011), you can also use the "for-each" loop:

### Example

int myNumbers[5] = {10, 20, 30, 40, 50};
for (int i : myNumbers) {
cout << i << "\n";
}
Try it Yourself »

It is good to know the different ways to loop through an array, since you may encounter them all in different programs.

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