Given two strings, copy one string to another using recursion. We basically need to write our own recursive version of strcpy in C/C++
Examples:
Input : s1 = "hello"
s2 = "geeksforgeeks"
Output : s2 = "hello"
Input : s1 = "geeksforgeeks"
s2 = ""
Output : s2 = "geeksforgeeks"
Iterative: Copy every character from s1 to s2 starting from index = 0 and in each call increase the index by 1 until s1 doesn't reach to end;
Implementation:
// Iterative CPP Program to copy one String
// to another.
#include <bits/stdc++.h>
using namespace std;
// Function to copy one string to other
// assuming that other string has enough
// space.
void myCopy(char s1[], char s2[])
{
int i = 0;
for (i=0; s1[i] != '\0'; i++)
s2[i] = s1[i];
s2[i] = '\0';
}
// Driver function
int main()
{
char s1[100] = "GEEKSFORGEEKS";
char s2[100] = "";
myCopy(s1, s2);
cout << s2;
return 0;
}
// Iterative Java Program to copy one String
// to another.
class GFG
{
// Function to copy one string to other
// assuming that other string has enough
// space.
static void myCopy(char s1[], char s2[])
{
int i = 0;
for (i = 0; i < s1.length; i++)
s2[i] = s1[i];
}
// Driver code
public static void main(String[] args)
{
char s1[] = "GEEKSFORGEEKS".toCharArray();
char s2[] = new char[s1.length];
myCopy(s1, s2);
System.out.println(String.valueOf(s2));
}
}
// This code contributed by Rajput-Ji
## Iterative Python Program to copy one String
# to another.
# Function to copy one string to other
def myCopy(s1,s2):
# traversing the string s1 from start to end
for i in range(len(s1)):
# copying value one by one
s2[i]=s1[i]
return "".join(s2)
#Driver code
s1=list("GEEKSFORGEEKS")
s2=[""]*len(s1)
print(myCopy(s1,s2))
'''Code is contributed by RAJAT KUMAR (rajatkumargla19)'''
// Iterative C# Program to copy one String
// to another.
using System;
class GFG
{
// Function to copy one string to other
// assuming that other string has enough
// space.
static void myCopy(char []s1, char []s2)
{
int i = 0;
for (i = 0; i < s1.Length; i++)
s2[i] = s1[i];
}
// Driver code
public static void Main(String[] args)
{
char []s1 = "GEEKSFORGEEKS".ToCharArray();
char []s2 = new char[s1.Length];
myCopy(s1, s2);
Console.WriteLine(String.Join("", s2));
}
}
// This code is contributed by 29AjayKumar
<script>
// Iterative Javascript Program to copy one String
// to another.
// Function to copy one string to other
// assuming that other string has enough
// space.
function myCopy(s1, s2)
{
let i = 0;
for (i = 0; i < s1.length; i++)
s2[i] = s1[i];
}
// Driver code
// Driver Code
let s1 = "GEEKSFORGEEKS";
let s2 = [];
let index = 0;
myCopy(s1, s2, index);
document.write(s2.join(""));
// This code contributed by shivanisinghss2110
</script>
Output
GEEKSFORGEEKS
Time Complexity: O(m), Here m is the length of string s1.
Auxiliary Space: O(1), As constant extra space is used.
Recursive: Copy every character from s1 to s2 starting from index = 0 and in each call increase the index by 1 until s1 doesn't reach to end;
Implementation:
// CPP Program to copy one String to
// another using Recursion
#include <bits/stdc++.h>
using namespace std;
// Function to copy one string in to other
// using recursion
void myCopy(char s1[], char s2[], int index = 0)
{
// copying each character from s1 to s2
s2[index] = s1[index];
// if string reach to end then stop
if (s1[index] == '\0')
return;
// increase character index by one
myCopy(s1, s2, index + 1);
}
// Driver function
int main()
{
char s1[100] = "GEEKSFORGEEKS";
char s2[100] = "";
myCopy(s1, s2);
cout << s2;
return 0;
}
// Java Program to copy one String to
// another using Recursion
class GFG
{
// Function to copy one string in to other
// using recursion
static void myCopy(char s1[],
char s2[], int index)
{
// copying each character from s1 to s2
s2[index] = s1[index];
// if string reach to end then stop
if (index == s1.length - 1)
{
return;
}
// increase character index by one
myCopy(s1, s2, index + 1);
}
// Driver Code
public static void main(String[] args)
{
char s1[] = "GEEKSFORGEEKS".toCharArray();
char s2[] = new char[s1.length];
int index = 0;
myCopy(s1, s2, index);
System.out.println(String.valueOf(s2));
}
}
// This code is contributed by PrinciRaj1992
# recursive Python Program to copy one String
# to another.
# Function to copy one string to other
def copy_str(x, y):
if len(y) == 0:
return x
else:
c = copy_str(x, (y)[1:-1])
return c
x = input("hello")
y = input("no")
print(copy_str(x, y))
# This code contributed by deeksha20049@iiid.ac.in
// C# Program to copy one String to
// another using Recursion
using System;
class GFG
{
// Function to copy one string in to other
// using recursion
static void myCopy(char []s1,
char []s2, int index)
{
// copying each character from s1 to s2
s2[index] = s1[index];
// if string reach to end then stop
if (index == s1.Length - 1)
{
return;
}
// increase character index by one
myCopy(s1, s2, index + 1);
}
// Driver Code
public static void Main(String[] args)
{
char []s1 = "GEEKSFORGEEKS".ToCharArray();
char []s2 = new char[s1.Length];
int index = 0;
myCopy(s1, s2, index);
Console.WriteLine(String.Join("", s2));
}
}
// This code is contributed by Princi Singh
<script>
// Javascript program to copy one String to
// another using Recursion
// Function to copy one string in to other
// using recursion
function myCopy(s1, s2, index)
{
// Copying each character from s1 to s2
s2[index] = s1[index];
// If string reach to end then stop
if (index == s1.length - 1)
{
return;
}
// Increase character index by one
myCopy(s1, s2, index + 1);
}
// Driver Code
var s1 = "GEEKSFORGEEKS";
var s2 = [];
var index = 0;
myCopy(s1, s2, index);
document.write(s2.join(""));
// This code is contributed by gauravrajput1
</script>
Output:
GEEKSFORGEEKS
Time Complexity: O(m), Here m is the length of string s1.
Auxiliary Space: O(m), due to recursive call stack