递归打印给定的模式

给定一个正整数n 。使用递归方法打印倒三角形图案（如下面的示例中所述）。

例子：

Input : n = 5
Output : 
* * * * *
* * * *
* * *
* *
*

Input : n = 7
Output :
* * * * * * *
* * * * * *
* * * * * 
* * * *
* * *
* *
*

方法 1（使用两个递归函数）：一个递归函数用于获取行号，另一个递归函数用于打印该特定行的星号。

算法：

printPatternRowRecur(n)
    if n < 1
        return
        
    print "* "
    printPatternRowRecur(n-1)

printPatternRecur(n)
    if n < 1
        return
    
    printPatternRowRecur(n)
    print "\n"
    printPatternRecur(n-1)

C++

// C++ implementation to print the given
// pattern recursively
#include 
using namespace std;
 
// function to print the 'n-th' row of the
// pattern recursively
void printPatternRowRecur(int n)
{
    // base condition
    if (n < 1)
        return;
         
    // print the remaining stars of the n-th row
    // recursively   
    cout << "* ";
    printPatternRowRecur(n-1);
}
 
void printPatternRecur(int n)
{
    // base condition
    if (n < 1)
        return;
     
    // print the stars of the n-th row   
    printPatternRowRecur(n);   
     
    // move to next line
    cout << endl;
     
    // print stars of the remaining rows recursively
    printPatternRecur(n-1);
     
}
 
// Driver program to test above
int main()
{
    int n = 5;
    printPatternRecur(n);
    return 0;
}

Java

// java implementation to print the given
// pattern recursively
import java.io.*;
 
class GFG
{
    // function to print the 'n-th' row
    // of the pattern recursively
    static void printPatternRowRecur(int n)
    {
        // base condition
        if (n < 1)
            return;
             
        // print the remaining stars
        // of the n-th row recursively
        System.out.print( "* ");
        printPatternRowRecur(n - 1);
    }
     
    static void printPatternRecur(int n)
    {
        // base condition
        if (n < 1)
            return;
         
        // print the stars of the n-th row
        printPatternRowRecur(n);
         
        // move to next line
        System.out.println ();
         
        // print stars of the
        // remaining rows recursively
        printPatternRecur(n - 1);
         
    }
 
    // Driver program to test above
    public static void main (String[] args)
    {
        int n = 5;
        printPatternRecur(n);
         
    }
}
//This code is contributed by vt_m

Python3

# Python 3 implementation
# to print the given
# pattern recursively
 
# function to print the
# 'n-th' row of the
# pattern recursively
def printPatternRowRecur(n):
 
    # base condition
    if (n < 1):
        return
         
    # print the remaining
    # stars of the n-th row
    # recursively
    print("*", end = " ")
    printPatternRowRecur(n - 1)
 
def printPatternRecur(n):
 
    # base condition
    if (n < 1):
        return
     
    # print the stars of
    # the n-th row
    printPatternRowRecur(n)
     
    # move to next line
    print("")
     
    # print stars of the
    # remaining rows recursively
    printPatternRecur(n - 1)
     
# Driver Code
n = 5
printPatternRecur(n)
 
# This code is contributed
# by Smitha

C#

// C# implementation to print the given
// pattern recursively
using System;
class GFG
{
    // function to print the 'n-th' row
    // of the pattern recursively
    static void printPatternRowRecur(int n)
    {
        // base condition
        if (n < 1)
            return;
             
        // print the remaining stars
        // of the n-th row recursively
        Console.Write( "* ");
        printPatternRowRecur(n - 1);
    }
     
    static void printPatternRecur(int n)
    {
        // base condition
        if (n < 1)
            return;
         
        // print the stars of the n-th row
        printPatternRowRecur(n);
         
        // move to next line
         Console.WriteLine();
         
        // print stars of the
        // remaining rows recursively
        printPatternRecur(n - 1);
         
    }
 
    // Driver program to test above
    public static void Main()
    {
        int n = 5;
        printPatternRecur(n);
         
    }
}
//This code is contributed by vt_m

Javascript

 
// JavaScript implementation to print the given
// pattern recursively
 
    // function to print the 'n-th' row
    // of the pattern recursively
function printPatternRowRecur(n)
{
    // base condition
    if (n < 1)
        return;
         
    // print the remaining stars
    // of the n-th row recursively
    document.write( "* ");
    printPatternRowRecur(n - 1);
}
 
function printPatternRecur(n)
{
    // base condition
    if (n < 1)
        return;
     
    // print the stars of the n-th row
    printPatternRowRecur(n);
     
    // move to next line
    document.write("<br>");
     
    // print stars of the
    // remaining rows recursively
    printPatternRecur(n - 1);
     
}
 
// Driver program to test above
var n = 5;
printPatternRecur(n);
 
// This code is contributed by Amit Katiyar
 

输出：

* * * * *
* * * *
* * *
* *
*

方法2（使用单个递归函数）：这种方法使用单个递归函数来打印整个图案。

算法：

printPatternRecur(n, i)
    if n < 1
        return
    
    if i <= n
        print "* "
        printPatternRecur(n, i+1)
        
    else
        print "\n"
        printPatternRecur(n-1, 1)

C++

// C++ implementation to print the given pattern recursively
#include 
 
using namespace std;
 
// function to print the given pattern recursively
void printPatternRecur(int n, int i)
{
    // base condition
    if (n < 1)
        return;
     
    // to print the stars of a particular row
    if (i <= n)
    {
        cout << "* ";
         
        // recursively print rest of the stars
        // of the row
        printPatternRecur(n, i + 1);
    }   
     
    else
    {
        // change line
        cout << endl;
         
        // print stars of the remaining rows recursively
        printPatternRecur(n-1, 1);
    }
}
 
// Driver program to test above
int main()
{
    int n = 5;
    printPatternRecur(n, 1);
    return 0;   
}

Java

// java implementation to
// print the given pattern recursively
import java.io.*;
 
class GFG {
     
    // function to print the
    // given pattern recursively
    static void printPatternRecur(int n, int i)
    {
        // base condition
        if (n < 1)
            return;
         
        // to print the stars of
        // a particular row
        if (i <= n)
        {
            System.out.print ( "* ");
             
            // recursively print rest 
            // of the stars of the row
            printPatternRecur(n, i + 1);
        }
         
        else
        {
            // change line
            System.out.println( );
             
            // print stars of the
            // remaining rows recursively
            printPatternRecur(n - 1, 1);
        }
    }
     
    // Driver program
    public static void main (String[] args)
    {
        int n = 5;
        printPatternRecur(n, 1);
         
    }
}
 
// This code is contributed by vt_m

Python3

# Python3 implementation to print the
# given pattern recursively
 
# function to print the given pattern
# recursively
def printPatternRecur(n, i):
 
    # base condition
    if (n < 1):
        return
     
    # to print the stars of a
    # particular row
    if (i <= n):
     
        print("* ", end = "")
         
        # recursively print rest of
        # the stars of the row
        printPatternRecur(n, i + 1)
     
    else:
     
        # change line
        print("")
         
        # print stars of the remaining
        # rows recursively
        printPatternRecur(n-1, 1)
 
# Driver program to test above
n = 5
printPatternRecur(n, 1)
 
# This code is contributed by Smitha

C＃

// C# implementation to
// print the given pattern recursively
using System;
class GFG {
     
    // function to print the
    // given pattern recursively
    static void printPatternRecur(int n, int i)
    {
        // base condition
        if (n < 1)
            return;
         
        // to print the stars of
        // a particular row
        if (i <= n)
        {
            Console.Write ( "* ");
             
            // recursively print rest
            // of the stars of the row
            printPatternRecur(n, i + 1);
        }
         
        else
        {
            // change line
            Console.WriteLine( );
             
            // print stars of the
            // remaining rows recursively
            printPatternRecur(n - 1, 1);
        }
    }
     
    // Driver program
    public static void Main ()
    {
        int n = 5;
        printPatternRecur(n, 1);
         
    }
}
 
// This code is contributed by vt_m

Javascript

 
// JavaScript implementation to print
// the given pattern recursively
 
// Function to print the given
// pattern recursively
function printPatternRecur(n, i)
{
     
    // Base condition
    if (n < 1)
        return;
     
    // To print the stars of
    // a particular row
    if (i <= n)
    {
        document.write("*" + "  ");
         
        // Recursively print rest of the stars
        // of the row
        printPatternRecur(n, i + 1);
    }
    else
    {
         
        // Change line
        document.write("<br>");
         
        // Print stars of the remaining
        // rows recursively
        printPatternRecur(n - 1, 1);
    }
}
 
// Driver code
var n = 5;
printPatternRecur(n, 1);
 
// This code is contributed by rdtank
 

输出：

* * * * *
* * * *
* * *
* *
*