# C++ Exercises: Check whether a number is prime or not

## C++ For Loop: Exercise-5 with Solution

Write a program in C++ to check whether a number is prime or not.

**Pictorial Presentation:**

**Sample Solution** :-

**C++ Code :**

```
#include <iostream>
using namespace std;
int main()
{
int num1, ctr = 0;
cout << "\n\n Check whether a number is prime or not:\n";
cout << "--------------------------------------------\n";
cout << " Input a number to check prime or not: ";
cin>> num1;
for (int a = 1; a <= num1; a++)
{
if (num1 % a == 0)
{
ctr++;
}
}
if (ctr == 2)
{
cout << " The entered number is a prime number. \n";
}
else {
cout << " The number you entered is not a prime number. \n";
}
}
```

Sample Output:

Check whether a number is prime or not: -------------------------------------------- Input a number to check prime or not: 13 The entered number is a prime number.

**Flowchart: **

**C++ Code Editor:**

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**Previous:** Write a program in C++ to find the perfect numbers between 1 and 500.

**Next:** Write a program in C++ to find prime number within a range.

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