11. Program to calculate COMBINATION and PERMUTATION with simple steps

#program to calculate the combination and permutation

def factorial(number):

    c=1

    if(number==0):

        return 1

    for i in range(number,0,-1):

        c=c*i

    return c

def combination():

    print('welcome to the combination finding')

    print()

    print('''Our format is as follows:

we will ask a and b as aCb  means a combiantion b''')

    a=int(input('enter a of the combination'))

    b=int(input('enter b of the combination'))

    print('you want to find',a,'C',b)

    if(a>=b):

        

        return factorial(a)/(factorial(b)*factorial(a-b))

    else:

        print('you have written a less than b which is incorrect')

def permutation():

    print('welcome to the permutation finding')

    print('''Our format is as follows:

we will ask a and b as aPb  means a permuatation b''')

    a=int(input('enter a of the permuatation'))

    b=int(input('enter b of the permuatation'))

    print('you want to find',a,'P',b)

    if(a>=b):

        return factorial(a)/factorial(b)

print('hello this is to calculate the combination and permutation')

print('''YOU ARE REQUESTED TO FOLLOW THE FORMAT TO CALCULATE THE SAME

''')

choice=int(input('''please write 1-combination

   and       2-Permutation'''))

if(choice==1):

    result=combination()

    print('result=',int(result))

elif(choice==2):

    result=permutation()

    print('result=',int(result))

else:

    print('you have entered wrong key')