# Check if All elements in Array are equal to value in C++

This tutorial will discuss about a unique way to check if all elements in array are equal to value in C++.

To check if all elements of array matches with a given value, we are going to use the STL algorithm `std::all_of()`.

Inside STL algorithm `std::all_of()` we will pass 3 arguments,

• Pointer pointing to the start of array.
• Pointer pointing to the end of array
• A Lambda function, which accepts an element as an argument and returns true if the given element is equal to a given value.

The `std::all_of()` function will apply the given Lambda function on all the elements of the array. If for all the elements the lambda function returns true, then the `std::all_of()` function will return true.

If there is a single element in array that is not equal to the given value, then the `std::all_of()` function returns false.

Like, in the below example we will check if all the elements of array are equal to value 15.

Let’s see the complete example,

```#include <iostream>
#include <algorithm>

int main()
{
int arr[] = { 15, 15, 15, 15, 15 };

int value = 15;

// Get the size of array
size_t len = sizeof(arr)/sizeof(arr);

// Check if all elements of array arr are equal to a value
bool result = std::all_of(arr,
arr + len,
[&value](bool elem){
return elem == value;
});

if (result)
{
std::cout << "Yes, all elements of array are equal to 15." << std::endl;
}
else
{
std::cout << "No, all elements of array are not equal to 15." << std::endl;
}

return 0;
}
```

Output :

```No, all elements of array are not equal to 15.
```

## Summary

Today we learned about several ways to check if all elements in array are equal to value in C++. Thanks.

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