How to check if a string is a subsequence of another string

# Recursive Python program to check if a string is subsequence 
# of another string 
  
# Returns true if str1[] is a subsequence of str2[]. 
def isSubSequence(string1, string2): 
    m = len(string1) 
    n = len(string2) 
    # Base Cases 
    if m == 0:    return True
    if n == 0:    return False
  
    # If last characters of two strings are matching 
    if string1[m-1] == string2[n-1]: 
        return isSubSequence(string1, string2, m-1, n-1) 
  
    # If last characters are not matching 
    return isSubSequence(string1, string2, m, n-1) 
  
# Driver program to test the above function 
string1 = "gksrek"
string2 = "geeksforgeeks"
  
if isSubSequence(string1, string2): 
    print "Yes"
else: 
    print "No"
  
# This code is contributed by BHAVYA JAIN 

// Iterative C++ program to check if a string is subsequence of another string 
#include<iostream> 
#include<cstring> 
using namespace std; 
  
// Returns true if str1[] is a subsequence of str2[]. m is 
// length of str1 and n is length of str2 
bool isSubSequence(char str1[], char str2[], int m, int n) 
{ 
   int j = 0; // For index of str1 (or subsequence 
  
   // Traverse str2 and str1, and compare current character  
   // of str2 with first unmatched char of str1, if matched  
   // then move ahead in str1 
   for (int i=0; i<n&&j<m; i++) 
       if (str1[j] == str2[i]) 
         j++; 
  
   // If all characters of str1 were found in str2 
   return (j==m); 
} 
  
// Driver program to test methods of graph class 
int main() 
{ 
    char str1[] = "gksrek"; 
    char str2[] = "geeksforgeeks"; 
    int m = strlen(str1); 
    int n = strlen(str2); 
    isSubSequence(str1, str2, m, n)? cout << "Yes ": 
                                     cout << "No"; 
    return 0; 
}