Prime Number

Definition:

A Prime Number is a number that has exactly two factors:

1
The number itself

Examples: 2, 3, 5, 7, 11, 13

Not Prime: 4, 6, 8, 9, 10 (because they have more than two factors).

Algorithm:

1.Start

2.Read the number n

3.Initialize i = 1 and count = 0

4.Check whether i <= n

5.If n % i == 0, increment count by 1

6.Increment i by 1

7.Repeat steps 4 to 6 until i > n

8.If count == 2, print "Prime Number"

9.Otherwise, print "Not a Prime Number"

10.Stop.

Flowchart:

  ┌───────┐
  │ Start │
  └───┬───┘
      │
      ▼

┌─────────────┐
│ Input n │
└─────┬───────┘
│
▼
┌─────────────┐
│ i = 1 │
│ count = 0 │
└─────┬───────┘
│
▼
┌───────┐
│i <= n?│
└──┬─┬──┘
Yes No
│ │
▼ ▼
┌─────────┐
│count=2 ?│
└──┬───┬──┘
Yes No
│ │
▼ ▼
┌────────┐ ┌────────────┐
│ Print │ │ Print │
│ Prime │ │ Not Prime │
└────┬───┘ └─────┬──────┘
│ │
▼ ▼
┌───────┐
│ Stop │
└───────┘

(If i <= n)

    ▼

┌─────────┐
│n % i=0 ?│
└──┬───┬──┘
Yes No
│ │
▼ │
┌───────────┐
│count+=1 │
└─────┬─────┘
│
▼
┌─────────┐
│ i=i+1 │
└────┬────┘
│
└──────► Back to i <= n

code:

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

i = 1
count = 0

while i <= n:
    if n % i == 0:
        count += 1
    i += 1

if count == 2:
    print("Prime Number")
else:
    print("Not a Prime Number")

Output 1

Input:

Enter a number: 7

Output:

Prime Number

Output 2

Input:

Enter a number: 8

Output:

Not a Prime Number