**Check a number is Prime or not**

**Check a number is Prime or not**

Write a C++ Program to Check given number is Prime number or not. Here’s simple C++ Program to Check given number is Prime number or not in C++ Programming Language.

A **prime number** is a natural number greater than 1 that has no positive divisors other than 1 and itself. It means a prime number is only divisible by 1 and itself, and it start from 2. The smallest prime number is 2

Here is source code of the C++ Program to Check given number is Prime number or not. The C++ program is successfully compiled and run(on Codeblocks) on a Windows system. The program output is also shown in below.

**SOURCE CODE : :**

**SOURCE CODE : :**

/* C++ Program to Check given number is Prime number or not */ #include<iostream> using namespace std; int main() { int i,n; cout<<"Enter any positive number :: "; cin>>n; if(n==1) { cout<<"\nSmallest prime number is :: 2"; } for(i=2;i<n;i++) { if(n%i==0) { cout<<"\nThe Entered Number [ "<<n<<" ] is NOT a prime number.\n"; break; } } if(n==i) { cout<<"\nThe Entered Number [ "<<n<<" ] is a prime number.\n"; } return 0; }

**Output : :**

**Output : :**

/* C++ Program to Check given number is Prime number or not */ Enter any positive number :: 97 The Entered Number [ 97 ] is a prime number. Process returned 0

Above is the source code for C++ Program to Check given number is Prime number or not which is successfully compiled and run on Windows System.The Output of the program is shown above .

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if i=10 and n=10 i,e n=i, is n(10)prime?

but it’s not possible,Since we create a condition ::

if(n%i==0)

then break;

#include <iostream>

using namespace std;

int n;

bool isnum = true;

int main()

{

cout << “enter the number ” << endl;

cin >> n;

if (n == 0 || n == 1)

{

isnum = false;

}

else{

for (int i=2; i <= n/2; ++i) {

if (n%i == 0) {

isnum = false;

break;

}

}

}

if (isnum) {

cout << “number is prime ” << endl;

}

else {

cout << “number is not prime ” << endl;

}

return 0;

}

#include <iostream>

#include <cmath>

using namespace std;

int main()

{

cout << “Enter a number:: “;

int num;

cin >> num;

if (num > 0) {

if ((num % 2 == 0) || (num % 3 == 0))

cout << “Not a Prime Number”;

else if ((num % 2 != 0) || (num % 3 != 0))

cout << ” Is a prime number”;

else

cout << “Invalid”;

}

return 0;

}

// Prime numbers: 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 61 67 71 73 79 83 89 97

totally wrong condition because 1 is not prime then 2 is prime and 3 is prime so test your code

//Write a C++ Program to Check a number is Prime or not // Prime numbers: 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 61 67 71 73 79 83 89 97 #include <iostream> #include <cmath> using namespace std; int main() { int num; cout << “Enter a number “; cin >> num; if (num <=1) { cout<<“prime number is start from 2”; } else if(num==2 || num==3) { cout<<“prime numbr”; } else if ((num % 2 == 0) || (num % 3 == 0)) { cout << “Not a Prime Number”; }… Read more »

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Mind

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