added rotate 2D array

Author: reethikprasad

Arrays/15. Rotate 2D array.cpp

@@ -0,0 +1,82 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+//Rotate anti clockwise by 90 degree
+void rotate(int a[][100],int n)
+{
+ for(int row=0;row<n;row++){
+ int s_c=0; //start column
+ int e_c=n-1; //end column
+ if(s_c<e_c){
+ swap(a[row][s_c],a[row][e_c]);
+ s_c++;
+ e_c--;
+ }
+ }
+
+ //transpose
+ for(int i=0;i<n;i++){
+ for(int j=0;j<n;j++){
+ if(i<j){
+ swap(a[i][j],a[j][i]);
+ }
+ }
+}
+}
+
+int main()
+{
+ int row=0,col=0;
+ int a[100][100];
+ int m,n;
+ cout<<"Enter row and column"<<endl;
+ cin>>m>>n;
+
+ int val=1;
+ for(int row=0;row<m;row++){
+ for(col=0;col<n;col++){
+ a[row][col]=val;
+ val++;
+ cout<<a[row][col]<<" ";
+
+ }
+ cout<<endl;
+ }
+
+ cout<<"After rotating"<<endl;
+ rotate(a,n);
+
+ for(int row=0;row<m;row++){
+ for(col=0;col<n;col++){
+ cout<<a[row][col]<<" ";
+
+ }
+ cout<<endl;
+ }
+
+
+
+
+
+
+
+ return 0;
+}
+
+/*
+Output
+Enter row and column
+4
+4
+1 2 3 4
+5 6 7 8
+9 10 11 12
+13 14 15 16
+After rotating
+4 8 12 16
+2 6 10 14
+3 7 11 15
+1 5 9 13
+*/
+
+