C++ Useful pro

C++ program to find prime number in C++                

#include

#include

 void main()

 {

clrscr();

int number,count=0;

cout<<"Enter number to check it is prime or not ";

          cin>>number;

           for(int a=1;a<=number;a++)

               {

                if(number%a==0)

                   {

                  count++;

                   }

               }

       if(count==2)

         {

          cout<<" Prime number \n";

         }

       else

         {

          cout<<" Not a prime number \n";

         }

       getch();

       }

Program take hours, minutes, seconds and print it in 24 hours & 12 hours format

#include

#include

void main()

{

 clrscr();

int hours,mins,seconds,x;                         

 cout<<"Enter hours=";

 cin>>hours;

cout<<"\nEnter minutes=";

cin>>mins;

cout<<"\nEnter seconds=";

cin>>seconds;

 if(hours > 24)

{

cout<<"Invalid Entery";

}

else

 {

cout<<"\n24 Hours Format\n";

cout<<"Hours  :  Mins  :  Seconds\n"<<"  "<

 if(hours > 12)

{

hours=hours-12;

 cout<<"12 Hours Format\n";

cout<<"Hours  :  Mins  :  Seconds\n"<<"  "<

}

else

 {

cout<<"12 Hours Format\n";

     cout<<"Hours  :  Mins  :  Seconds\n"<<" "<

    }

  }  

}  

  

Program to find greatest number between 3 number using if else statement           

#include

using namespace std;

int main()

{

int num1,num2,num3;

cout<<" Enter value for first number";

cin>>num1;

cout<<" Enter value for second number";

cin>>num2;

cout<<" Enter value for third number";

cin>>num3;

if(num1>num2&&num1>num3)

{

cout<<" First number is greatest:"<

}

else if(num2>num1&&num2>num3)

{

cout<<" Second number is greatest"<

}

else

{

cout<<" Third number is greatest"<

}

return 0;

}

C++ program to find factorial of number in c++

#include
#include
using namespace std;
int main()
{
    int num,factorial=1;
    cout<<" Enter number to find its factorial:  ";
    cin>>num;
    for(int a=1;a<=num;a++)
    {
        factorial=factorial*a;
    }
   cout<<"Factorial of given number is ="<     return 0;
}