21.Example programs using functions

Write a python function to find the area of a circle.

def circlearea (radius): 

    area=3.14*(radius**2)

    return area

#function call

r=int(input("Enter radius.."))

area=circlearea(r)

print("Area of the circle=",area)

output

Enter radius..2

Area of the circle= 12.56

Compute nCr using a factorial function

def fact(n):

    f=1

    for i in range(1,n+1):

        f=f*i

    return f

print("Program to compute nCr...")

n=int(input("Enter n.."))

r=int(input("Enter r..."))

ncr=fact(n)/(fact(n-r)*fact(r))

print("nCr...",ncr)

output

Program to compute nCr...

Enter n..5

Enter r...3

nCr... 10.0

Python function to extract digits and checks whether all the digits are even or not

def digit(n):

    flag=1

    while n!=0:

        d=n%10

        if d%2!=0:

            flag=0

            break

        n=n//10

    return flag

n=int(input("Enter a number::"))

if digit(n):

    print("All digits are even")

else:

    print("All digits are not even")

           
Menu driven program to implement the following i)check even or odd ii)check number is positive negative or zero iii) generate factors of a number ( university question)

def evenodd(n):

    if n%2==0:

        print("even")

    else:

        print("odd")

def postvnegtv(n):

    if n>0:

        print("+ve")

    elif n<0:

        print("-ve")

    else:

        print("zero")

def  factors(n):

    print ("factors")

    for i in range(1,n+1):

        if n%i==0:

            print (i,end=' ')

while True:

     print("\n....Menu...\n1.even or odd\n2.postv or negtv \n3.factors\n4..exit\n")

     ch=int(input("Enter your choice---"))

     if ch==4:

         break

     n=int(input("Enter a number.."))

     if ch==1:

         evenodd(n)

     if ch==2:

         postvnegtv(n)

     if ch==3:

         factors(n)

Write a Python program to find the value for sin(x) up to n terms using the series

sin(x)=1-x^3/3!+x^5/5!..... (      sin(x) = ((-1)^n/(2n+1)!)x^(2n+1)   )

import math

def sinseries(x,n):

    sine = 0

    for i in range(n):

        sign = (-1)**i

        x=x*(math.pi/180)

        sine = sine + ((x**(2.0*i+1))/math.factorial(2*i+1))*sign

    return sine

x=int(input("Enter the value of x in degrees:"))

n=int(input("Enter the number of terms:"))

print(round(sinseries(x,n),2))

output:

Enter the value of x in degrees:30

Enter the number of terms:10

0.5

Note: you can replace factorial() function in math module with your own function

Create a function min_max() that takes n numbers as list argument and return the smallest and largest numbers.(university question)

def min_max(l,n):
    small=l[0];
    large=l[0];
    for i in range(1,n):
        if l[i]>large:
            large=l[i]
        if l[i]<small:
            small=l[i]
        return(small,large)
n=int(input('Enter n'))
print('Enter numbers')
l=[]
for i in range(n):
    x=int(input())
    l.append(x)
(small,large)=min_max(l,n)
print("Small=",small," large=",large) 

Write a Python program using function to find the sum of first ‘n’ even numbers and return the result to main program.( university question)

def sum_even(n):
    s=0
    for i in range(2*n+1):
        if i%2==0:
            s=s+i
    return s
sum=sum_even(2)
print(sum)

Write a Python program to create a set of functions that compute the mean, median and mode of a set of numbers. Each function should expect a list of numbers as an argument and return a single number. Each function should return 0 if the list is empty. Include a main function that tests the three functions with a given list. ( university question)

( Hint: Mean: Mean is the average value of a list of numbers.Median: If the number of values in a list is odd, the median of the list is the value at the midpoint when the set of numbers is sorted; otherwise, the median is the average of the two values surrounding the midpoint. Mode: The mode of a list of values is the value that occurs most frequently)

def median(lst):

      n=len(lst)

      lst.sort()

      mid=n//2

      if n%2==1:

         return (lst[mid])

      else:

         return ((lst[mid]+lst[mid-1])/2)

def mean(lst):

      n=len(lst)

      return(sum(lst)/n)

def mode(lst):

      nc={}

      md={}

      for i in lst:

            nc[i]=lst.count(i)

      maxcount=max(nc.values())

      for k in nc:

          if nc[k]==maxcount:

              md[k]=maxcount

      return(md)

lst=[3,3,4,6,2,2,7,8,9]

print("Mean=",mean(lst))

print("Median=",median(lst))

print("Mode=",mode(lst))

Write a python program to find X^Y or pow(X,Y) without using standard function(University Question)

def pow(x,y):

    p=1

    while y:

        p=p*x

        y=y-1

    return p

x=3

y=5

print(f'{x}^{y}=',pow(x,y))