# Program to implement Linear Search C++

Here we will write a program to implement Linear Search C++ programming language, so first lets start with what is linear search and then we will write a program in C++ to implement Linear Search.

## What is Linear Search:

Linear search or sequential search is a method for finding a target value within a list. It sequentially checks each element of the list for the target value until a match is found or until all the elements have been searched.

Given a list L of n elements with values or records L0 …. Ln−1, and target value T, the following subroutine uses linear search to find the index of the target T in L.

1. Set i to 0.
2. If Li = T, the search terminates successfully; return i.
3. Increase i by 1.
4. If i < n, go to step 2. Otherwise, the search terminates unsuccessfully.

#### Time Complexity:

Worst Case: Linear search runs in at worst linear time and makes at most n comparisons, where n is the length of the list.

Average Case: The average time it takes is n+1/2, where n is the number of elements in the list/series/sequence.

Now lets implement Linear search C++ using above steps:

### Program to implement Linear Search C++:

```#include<iostream>
using namespace std;

int main() {
cout<<"Enter The Size Of Array: ";
int size;
cin>>size;

int array[size], key,i;

// Taking Input In Array
for(int j=0;j<size;j++){
cout<<"Enter "<<j<<" Element: ";
cin>>array[j];
}

for(int a=0;a<size;a++){
cout<<"array[ "<<a<<" ] = ";
cout<<array[a]<<endl;
}

cout<<"Enter Key To Search in Array";
cin>>key;

for(i=0;i<size;i++){
if(key==array[i]){
cout<<"Key Found At Index Number : "<<i<<endl;
break;
}
}

if(i != size){
cout<<"KEY FOUND at index : "<<i;
}
else{
}
return 0;
}```

### OUTPUT:

```Enter The Size Of Array: 5
Enter 0 Element: 8
Enter 1 Element: 2
Enter 2 Element: 1
Enter 3 Element: 3
Enter 4 Element: 9
array[ 0 ] = 8
array[ 1 ] = 2
array[ 2 ] = 1
array[ 3 ] = 3
array[ 4 ] = 9
Enter Key To Search in Array2
Key Found At Index Number : 1
KEY FOUND at index : 1

...Program finished with exit code 0
Press ENTER to exit console.```

Comment in case of any suggestions or issues.