added program of subsequences of string

algorithms/strings/all_subsequences_of_string.cpp

@@ -0,0 +1,31 @@
+#include <iostream>
+
+using namespace std;
+
+//Print All Subsequences Of String
+void printAllSubsequences(string &input, int i, string t){
+    // i  to keep track of string indexes
+    if(i == input.length()){
+        cout<<t<<endl;
+        return;
+    }
+
+    //For element select it in out subsequence once and leave it out once
+    printAllSubsequences(input, i+1, t+input[i]);
+    printAllSubsequences(input, i+1, t);
+
+}
+
+
+
+int main(){
+    string input;
+    cout<<"Enter the string of which you want to find subsequences"<<endl;
+    cin >> input;
+
+    cout<<"Subsequences of string are: "<<endl;
+    printAllSubsequences(input, 0, "");
+
+}
+
+