Added counting sort

Sorting_Algorithms/Counting_Sort/count_sort.cpp

@@ -0,0 +1,66 @@
+// C++ Program for counting sort 
+#include<bits/stdc++.h> 
+#include<string.h> 
+using namespace std; 
+#define RANGE 255 
+
+// The main function that sort 
+// the given string arr[] in 
+// alphabatical order 
+void countSort(char arr[]) 
+{ 
+	// The output character array 
+	// that will have sorted arr 
+	char output[strlen(arr)]; 
+
+	// Create a count array to store count of inidividul 
+	// characters and initialize count array as 0 
+	int count[RANGE + 1], i; 
+	memset(count, 0, sizeof(count)); 
+
+	// Store count of each character 
+	for(i = 0; arr[i]; ++i) 
+		++count[arr[i]]; 
+
+	// Change count[i] so that count[i] now contains actual 
+	// position of this character in output array 
+	for (i = 1; i <= RANGE; ++i) 
+		count[i] += count[i-1]; 
+
+	// Build the output character array 
+	for (i = 0; arr[i]; ++i) 
+	{ 
+		output[count[arr[i]]-1] = arr[i]; 
+		--count[arr[i]]; 
+	} 
+
+	/* 
+	For Stable algorithm 
+	for (i = sizeof(arr)-1; i>=0; --i) 
+	{ 
+		output[count[arr[i]]-1] = arr[i]; 
+		--count[arr[i]]; 
+	} 
+
+	For Logic : See implementation 
+	*/
+
+	// Copy the output array to arr, so that arr now 
+	// contains sorted characters 
+	for (i = 0; arr[i]; ++i) 
+		arr[i] = output[i]; 
+} 
+
+// Driver code 
+int main() 
+{ 
+	char arr[] = "geeksforgeeks"; 
+
+	countSort(arr); 
+
+	cout<< "Sorted character array is " << arr; 
+	return 0; 
+} 
+
+// This code is contributed by rathbhupendra 
+