# Array algorithms in C++ STL

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Since C++11 there are different functions added into the STL. These functions are present at algorithm header file. Here we will see some functions of this.

• The all_of() function is used to check one condition, that is true for all elements of a container. Let us see the code to get the idea

## Example

#include <iostream>
#include <algorithm>
using namespace std;
main() {
int arr[] = {2, 4, 6, 8, 10};
int n = sizeof(arr)/sizeof(arr[0]);
if(all_of(arr, arr + n, [](int x){return x%2 == 0;})) {
cout << "All are even";
} else {
cout << "All are not even";
}
}

## Output

All are even

• The any_of() function is used to check one condition, that is true for at least one element of a container. Let us see the code to get the idea.

## Example

#include <iostream>
#include <algorithm>
using namespace std;
main() {
int arr[] = {2, 4, 6, 8, 10, 5, 62};
int n = sizeof(arr)/sizeof(arr[0]);
if(any_of(arr, arr + n, [](int x){return x%2 == 1;})) {
cout << "At least one element is odd";
} else {
cout << "No odd elements are found";
}
}

## Output

At least one element is odd

• The none_of() function is used to check whether no element of a container is satisfies the given condition. Let us see the code to get the idea.

## Example

#include <iostream>
#include <algorithm>
using namespace std;
main() {
int arr[] = {2, 4, 6, 8, 10, 5, 62};
int n = sizeof(arr)/sizeof(arr[0]);
if(none_of(arr, arr + n, [](int x){return x < 0 == 1;})) {
cout << "All elements are positive";
} else {
cout << "Some elements are negative";
}
}

## Output

All elements are positive

• The copy_n() function is used to copy elements of one array into another array. Let us see the code to get better idea.

## Example

#include <iostream>
#include <algorithm>
using namespace std;
main() {
int arr[] = {2, 4, 6, 8, 10, 5, 62};
int n = sizeof(arr)/sizeof(arr[0]);
int arr2[n];
copy_n(arr, n, arr2);
for(int i = 0; i < n; i++) {
cout << arr2[i] << " ";
}
}

## Output

2 4 6 8 10 5 62

• The itoa() function is used assign continuous values into array. This function is present under numeric header file. It takes three arguments. The array name, size and the starting value.

## Example

#include <iostream>
#include <numeric>
using namespace std;
main() {
int n = 10;
int arr[n];
iota(arr, arr+n, 10);
for(int i = 0; i < n; i++) {
cout << arr[i] << " ";
}
}

## Output

10 11 12 13 14 15 16 17 18 19
Published on 20-Aug-2019 07:39:58
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