Note: I have used pivot as the middle element each time.
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| #include <iostream> | |
| using namespace std; | |
| void quicksort(int a[],int left, int right) | |
| { | |
| int i,j,temp,pivot; | |
| i=left; | |
| j=right; | |
| pivot=a[(left+right)/2]; | |
| while(i<=j) | |
| { | |
| //For left side | |
| while(a[i]<pivot) i++; | |
| //For right side | |
| while(a[j]>pivot) j--; | |
| // a[i], which is greater than the pivot and a[j], which is less than the pivot, those two are swapping, | |
| // to make the all the elements left of the pivot, smaller than the pivot and right of the pivot, greater than the pivot | |
| if(i<=j) | |
| { | |
| swap(a[i],a[j]); | |
| /* Since after the swap, a[i] is smaller than the pivot & a[j] is greater than the pivot, | |
| so there is no need to start checking from i or j, that's why i++ and j-- is done */ | |
| i++; | |
| j--; | |
| } | |
| } | |
| // After this loop, the left side of the present pivot is smaller and the right side is greater. | |
| // Now it's turn to quick sort the left and the right part | |
| if(left<j) | |
| { | |
| quicksort(a,left,j); | |
| } | |
| if(right>i) | |
| { | |
| quicksort(a,i,right); | |
| } | |
| } | |
| int main() | |
| { | |
| int n,l; | |
| cout<<"Enter the size of the array : "<<endl; | |
| cin>>n; | |
| int ar[n]; | |
| cout<<"Enter the unsorted array elements : "<<endl; | |
| for(l=0;l<n;l++) cin>>ar[l]; | |
| quicksort(ar,0,n-1); | |
| cout<<"The sorted array : "<<endl; | |
| for(l=0;l<n;l++) | |
| { | |
| cout<<ar[l]<<endl; | |
| } | |
| return 0; | |
| } |
Fall out, Codes! 