Linear Search means to traverse a given list or array one by one sequencially starting from the first element with the element to be searched until a match is found or end of the array is reached.

so in the above figure element to be searched is 5 and it is found at index 6.

if the match is found index of the matched element is retured else -1 is returned

Examples :
`Input : arr[] = {11,8,34,2,3,76}          N=6,key = 3;Output : 4Element 3 is present at index 4Input : arr[] = {10, 20, 30, 60, 50, 110, 100}           N=7,key = 175;Output : -1Element 175 is not present in arr[].`

implementation:
```int search(int arr[], int N, int key)
{

// Start traversing the array
for (int i = 0; i < N; i++)
{
// If a successful match is found,
// output the index
if (arr[i] == key)
return i;
}

// and end of array is reached
return -1;
} ```

Time Complexity: O(N)

lets implement the same code using cout in c++:

```int search(int arr[], int N, int key)
{

int p=0;

// Start traversing the array
for (int i = 0; i < N; i++)
{
// if the some array element is equal to element to be searched
if (arr[i] == key)
{
cout<< i;
p++;
break;
}
}
// if p=0 than element to be searched is found