print the pattern using recursion-CodePudding

i want the print the below pattern using recursion and do not have to use any loops(strictly).

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

i have did it without using recursion

n = 7
for i in range(n,0,-1):
    for j in range(i,0,-1):
        print("*",end=" ")
    for j in range(2*(n-i)):
        print(" ",end=" ")
    for j in range(i,0,-1):
        print("*",end=" ")
    print()

for i in range(1,n):
    for j in range(i 1):
        print("*",end=" ")
    for j in range(2*(n-i-1)):
        print(" ",end=" ")
    for j in range(i 1):
        print("*",end=" ")
    print()

can anyone help in printing the same patter using recursion and without using any loops(strictly)

i have tried using recursion but unable to print it properly and unable to visualize the code any further code using recursion:

def print_pattern(n, row=0):
    if row == n:
        return
    print("* "*(n - row)   "  "*(2*row)   "* "*(n - row))
    print_pattern(n, row   1)
    if row != 0:
        print("* "*(n - row)   "  "*(2*row)   "* "*(n - row))

n = 5
print_pattern(n)

CodePudding user response：

If the pattern always stays the same you could save it in a variable using var ='''pattern'''

In this case it would look like this:

pattern = '''* * * * * * * * * * * * * * 
* * * * * *     * * * * * *
* * * * *         * * * * *
* * * *             * * * *
* * *                 * * *
* *                     * *
*                         *
* *                     * *
* * *                 * * * 
* * * *             * * * *
* * * * *         * * * * *
* * * * * *     * * * * * *
* * * * * * * * * * * * * *'''

print(pattern)

CodePudding user response：

Use only row != -1 your code will work properly

def print_pattern(n, row=0):
    if row == n:
        return
    print("* "*(n - row)   "  "*(2*row)   "* "*(n - row))
    print_pattern(n, row   1)
    if row != -1:
        print("* "*(n - row)   "  "*(2*row)   "* "*(n - row))

n = 7
print_pattern(n)

CodePudding user response：

The check should be row != n - 1:

def print_pattern(n, row=0):
    if row == n:
        return
    print("* " * (n - row)   "  " * (2 * row)   "* " * (n - row))
    print_pattern(n, row   1)
    if row != n - 1:
        print("* " * (n - row)   "  " * (2 * row)   "* " * (n - row))


n = int(input('Number of lines:'))
print_pattern(n)