Description
Get a number as input from the user and check whether that number is prime or not.
A prime number is a number with factors as 1 and that number itself.
Input
1
Output
1 is not a prime number
Input
5
Output
5 is a prime number
C Program
Method 1
#include <stdio.h>
int main()
{
int i,count=0;
int num;
printf("Enter a number: ");
scanf("%d",&num);
for(i=1;i<=num;i++)
{
if(num%i==0)
count++;
}
if(num<=1)
printf("%d is not a prime number", num);
else if(count > 2)
printf("%d is not a prime number", num);
else
printf("%d is a prime number", num);
return 0;
}
Method 2
#include <stdio.h>
#include<stdlib.h>
int main()
{
int i,flag=0;
int num;
printf("Enter a number: ");
scanf("%d",&num);
if(num<=1)
{
printf("%d is not a prime number", num);
exit(1);
}
for(int i=2;i<=num/2;i++)
{
if(num%i==0)
{
flag=1;
break;
}
}
if(flag==1)
printf("%d is not a prime number", num);
else
printf("%d is a prime number", num);
return 0;
}
Method 3
#include <stdio.h>
#include<stdlib.h>
#include<math.h>
int main()
{
int i,flag=0;
int num;
printf("Enter a number: ");
scanf("%d",&num);
if(num<=1)
{
printf("%d is not a prime number", num);
exit(1);
}
for(int i=2;i<=sqrt(num);i++)
{
if(num%i==0)
{
flag=1;
break;
}
}
if(flag==1)
printf("%d is not a prime number", num);
else
printf("%d is a prime number", num);
return 0;
}
Method 4
#include <stdio.h>
#include<stdlib.h>
#include<math.h>
int main()
{
int i,flag=0;
int num;
printf("Enter a number: ");
scanf("%d",&num);
if(num<=1)
{
printf("%d is not a prime number", num);
exit(1);
}
for(int i=2;i<=sqrt(num);i=i+2)
{
if(num%i==0)
{
flag=1;
break;
}
}
if(flag==1)
printf("%d is not a prime number", num);
else
printf("%d is a prime number", num);
return 0;
}
C++ Program
Method 1
#include <iostream>
using namespace std;
int main()
{
int i,count=0;
int num;
cout<<"Enter a number: ";
cin>>num;
for(i=1;i<=num;i++)
{
if(num%i==0)
count++;
}
if(num<=1)
cout<<num<<" is not a prime number";
else if(count > 2)
cout<<num<<" is not a prime number";
else
cout<<num<<" is a prime number";
return 0;
}
Method 2
#include <iostream>
using namespace std;
int main()
{
int i,flag=0;
int num;
cout<<"Enter a number: ";
cin>>num;
if(num<=1)
{
cout<<num<<" is not a prime number";
exit(1);
}
for(int i=2;i<=num/2;i++)
{
if(num%i==0)
{
flag=1;
break;
}
}
if(flag==1)
cout<<num<<" is not a prime number";
else
cout<<num<<" is a prime number";
return 0;
}
Method 3
#include <iostream>
#include<math.h>
using namespace std;
int main()
{
int i,flag=0;
int num;
cout<<"Enter a number: ";
cin>>num;
if(num<=1)
{
cout<<num<<" is not a prime number";
exit(1);
}
for(int i=2;i<=sqrt(num);i++)
{
if(num%i==0)
{
flag=1;
break;
}
}
if(flag==1)
cout<<num<<" is not a prime number";
else
cout<<num<<" is a prime number";
return 0;
}
Method 4
#include <iostream>
#include<math.h>
using namespace std;
int main()
{
int i,flag=0;
int num;
cout<<"Enter a number: ";
cin>>num;
if(num<=1)
{
cout<<num<<" is not a prime number";
exit(1);
}
for(int i=2;i<=sqrt(num);i=i+2)
{
if(num%i==0)
{
flag=1;
break;
}
}
if(flag==1)
cout<<num<<" is not a prime number";
else
cout<<num<<" is a prime number";
return 0;
}
Java Program
Method 1
import java.util.Scanner;
public class Main
{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.println("Enter a number");
int num=sc.nextInt();
int count=0;
if(num<=1)
System.out.println(num+" is not a prime number");
else
{
for(int i=2;i<=num;i++)
{
if(num%i==0)
{
count++;
}
}
if(count>2)
System.out.println(num+" is not a prime number");
else
System.out.println(num+" is a prime number");
}
}
}
Method 2
import java.util.Scanner;
public class Main
{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.println("Enter a number");
int num=sc.nextInt();
int flag=0;
if(num<=1)
System.out.println(num+" is not a prime number");
else
{
for(int i=2;i<num;i++)
{
if(num%i==0)
{
flag=1;
break;
}
}
if(flag==1)
System.out.println(num+" is not a prime number");
else
System.out.println(num+" is a prime number");
}
}
}
Method 3
import java.util.Scanner;
public class Main
{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.println("Enter a number");
int num=sc.nextInt();
int flag=0;
if(num<=1)
System.out.println(num+" is not a prime number");
else
{
for(int i=2;i<=num/2;i++)
{
if(num%i==0)
{
flag=1;
break;
}
}
if(flag==1)
System.out.println(num+" is not a prime number");
else
System.out.println(num+" is a prime number");
}
}
}
Python
num=int(input("Enter a number: "))
flag=0
for i in range(2,num):
if num%i==0:
flag=1
break
if(num<=1):
print("Not a prime number")
elif(flag==1):
print("Not a prime number")
else:
print("Is a prime number")
