From 45ae0912a24ff4f1f953f8c0a803f2a1be2ab301 Mon Sep 17 00:00:00 2001
From: MEGHWANT SINGH <68533246+Meghwantsingh@users.noreply.github.com>
Date: Sun, 3 Oct 2021 08:09:00 +0530
Subject: [PATCH 1/4] Create binary-search.cpp

---
 .../searching/binary-search/binary-search.cpp | 49 +++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 arrays/searching/binary-search/binary-search.cpp

diff --git a/arrays/searching/binary-search/binary-search.cpp b/arrays/searching/binary-search/binary-search.cpp
new file mode 100644
index 0000000..5c0fab7
--- /dev/null
+++ b/arrays/searching/binary-search/binary-search.cpp
@@ -0,0 +1,49 @@
+
+//Binary search .................Iterative method best for sorted array
+
+# include<bits/stdc++.h>
+using namespace std; //std::cout or std::cin
+
+int main(){
+  int n,t;
+  cout<<"enter test cases"<<endl;
+  cin>>t;
+                               //cout<<(sizeof(arr)/sizeof(arr[0]));   sizeof(arr) = datatype of arr * number of variable
+  while(t--){
+        cout<<"enter size of array "<<endl;
+           cin>>n;
+    int arr[n];
+   
+    cout<<"Enter array element\n";
+    
+  for(int i=0;i<n;i++){
+    cin>>arr[i];
+    }
+
+    int key;
+    cout<<"enter key to search"<<endl;
+    cin>>key;
+
+    int low=0,high=n-1, flag=0;
+    for(int i=0;i<n;i++){
+                                                                // int mid =(low +high)/2; //It take more time 5.2 second
+                                                               // cout<<mid;
+       int mid=low+(high-low)/2;                      //     rather using (low+high)/2  we use this bez   It take less time 4.1 second
+       if(arr[mid]==key){
+        cout<<"present"<<endl;
+          flag=1;
+          break;
+       }
+       else if(arr[mid]>key){            
+             high= mid-1;
+       }
+       else if(arr[mid] <key)
+          low = mid+1;
+    }
+
+    if(flag==0){                             
+        cout<<"Not present"<<endl;
+    }
+  }
+  return 0;
+}

From 393106107620a8b5b3c7b333869a579c79fa2856 Mon Sep 17 00:00:00 2001
From: MEGHWANT SINGH <68533246+Meghwantsingh@users.noreply.github.com>
Date: Mon, 4 Oct 2021 11:04:36 +0530
Subject: [PATCH 2/4] Create linear-search.cpp

---
 .../searching/linear-search/linear-search.cpp | 39 +++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 arrays/searching/linear-search/linear-search.cpp

diff --git a/arrays/searching/linear-search/linear-search.cpp b/arrays/searching/linear-search/linear-search.cpp
new file mode 100644
index 0000000..af35591
--- /dev/null
+++ b/arrays/searching/linear-search/linear-search.cpp
@@ -0,0 +1,39 @@
+//Linear search key
+
+#include<bits/stdc++.h>
+using namespace std;
+int main(){
+ int n; // size of array
+ cout<<"enter size of array"<<endl;
+ cin>>n;
+ int arr[n]; // array to store all the elements
+ cout<<"Enter array element\n";
+ for(int i=0 ;i<n;i++){
+     cin>>arr[i]; // loop for entering array
+ }
+ int key; // key variable to be search
+ cout<<"enter key to be search"<<endl;
+ cin>>key;
+ int i =0 ,flag =0 ,count =0,lastpos;
+ for(i =0 ; i<n ;i++) {
+        if(key == arr[i]){
+           // cout<<"present"<<" "<<i+1<<endl;
+           lastpos=i+1;
+            flag =1;
+            break;
+           // break; using this break statment present will run only 1 time if same element array then it will stop at first time
+           // using break time compx O(1)
+           // without break we can print both 1 or all position of key present in array
+        }
+        count++;
+ }
+ if(flag == 0){
+    cout<<"Not present"<<endl;
+ } else {
+ cout<<"present \n position"<<lastpos<<endl; // time compx O(n)
+ //cout<<count<<endl;
+ }
+
+return 0;
+}
+

From 550da01ed3df1de24d7d507e9301e828af834c5c Mon Sep 17 00:00:00 2001
From: MEGHWANT SINGH <68533246+Meghwantsingh@users.noreply.github.com>
Date: Mon, 4 Oct 2021 11:20:40 +0530
Subject: [PATCH 3/4] Update linear-search.cpp

lastpos is used to give position of key to be search.
---
 arrays/searching/linear-search/linear-search.cpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arrays/searching/linear-search/linear-search.cpp b/arrays/searching/linear-search/linear-search.cpp
index af35591..e776c12 100644
--- a/arrays/searching/linear-search/linear-search.cpp
+++ b/arrays/searching/linear-search/linear-search.cpp
@@ -2,11 +2,13 @@
 
 #include<bits/stdc++.h>
 using namespace std;
+
 int main(){
- int n; // size of array
+ int n;                                // size of array
  cout<<"enter size of array"<<endl;
  cin>>n;
  int arr[n]; // array to store all the elements
+ 
  cout<<"Enter array element\n";
  for(int i=0 ;i<n;i++){
      cin>>arr[i]; // loop for entering array
@@ -30,10 +32,9 @@ int main(){
  if(flag == 0){
     cout<<"Not present"<<endl;
  } else {
- cout<<"present \n position"<<lastpos<<endl; // time compx O(n)
- //cout<<count<<endl;
+ cout<<"present \n position"<<lastpos<<endl;                      // time compx  O(n)
+  //cout<<count<<endl;
  }
 
 return 0;
 }
-

From 1a03cb1114ecc645b0b6566623f324b2c9bab487 Mon Sep 17 00:00:00 2001
From: MEGHWANT SINGH <68533246+Meghwantsingh@users.noreply.github.com>
Date: Tue, 5 Oct 2021 10:52:42 +0530
Subject: [PATCH 4/4] Create reversearray.cpp
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Reverse an array problem  done using C++ .Pls check if you got any error or mistake replay.
Github 👍 https://github.com/Meghwantsingh/Data-Structures-and-Algorithms/new/main/arrays/reverse-array
If I did something wrong sorry bez I am new to this.
---
 arrays/reverse-array/reversearray.cpp | 39 +++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 arrays/reverse-array/reversearray.cpp

diff --git a/arrays/reverse-array/reversearray.cpp b/arrays/reverse-array/reversearray.cpp
new file mode 100644
index 0000000..f8ff925
--- /dev/null
+++ b/arrays/reverse-array/reversearray.cpp
@@ -0,0 +1,39 @@
+
+// REVERSE AN ARRAY
+
+#include<iostream>
+using namespace std;
+
+void reArr(int arr[],int start ,int last){  // function to reverse array
+
+  int temp;
+
+  while(start <last){
+    temp =arr[start];        // simple swap
+    arr[start]=arr[last];
+    arr[last]=temp;
+    last--;
+    start++;
+  }
+}
+
+
+int main(){
+ int n;
+ cout<<"Enter size of array : ";
+ cin>>n;
+ int arr[n];
+ cout<<"Enter the element of array\n";
+
+  for(int i=0;i<n;i++){
+    cin>>arr[i];
+  }
+ reArr(arr,0,n-1);            //  function for reverse array element
+ cout<<"Reversed array\n";
+
+ for(int i=0;i<n;i++){
+    cout<<arr[i]<<" ";
+ }
+
+ return 0;
+}