Modified C++ Bubble sort (#19358)

Optimized by stopping the algorithm if there wasn't any swap(rest is sorted).
There was a syntax error(temp was not declared)

client/src/pages/guide/english/algorithms/sorting-algorithms/bubble-sort/index.md

@@ -114,17 +114,20 @@ void bubblesort(int arr[], int n)
 {
 	if(n==1)	//Initial Case
 		return;
-	
+	bool swap_flag = false;
 	for(int i=0;i<n-1;i++)	//After this pass the largest element will move to its desired location.
 	{
 		if(arr[i]>arr[i+1])
 		{
-			temp=arr[i];
+			int temp=arr[i];
 			arr[i]=arr[i+1];
 			arr[i+1]=temp;
+			swap_flag = true;
 		}
 	}
-	
+        // IF no two elements were swapped in the loop, then return, as array is sorted 
+	if(swap_flag == false)
+		return;
 	bubblesort(arr,n-1);	//Recursion for remaining array
 }
 ```