Factorial.cpp:

#include <iostream>
using namespace std;
int main() 
{
    int n, factorial = 1;
    cout << "Enter a positive integer: ";
    cin >> n;
    for (int i = 1; i <= n; ++i) {
        factorial *= i;   // factorial = factorial * i;
    }
   cout<< "Factorial of "<<n<<" = "<<factorial <<endl;
    return 0;
}



MatrixSum.cpp:

#include <iostream>
using namespace std;
int main()
{
    int a[2][3] = {
{5,10,20},
{8,6,5}
    };
    int b[2][3]= {
{3,8,5},
{2,9,3}
    };
    int i,j,s[2][3];
   
    for(i=0;i<2;i++)
    {
        for(j=0;j<3;j++)
        {
            cout << a[i][j] + b[i][j] << "   ";
        }
        cout << endl;
    }
    return 0;
}


PrimeNumbers.cpp:
#include <iostream>
using namespace std;
 
int main () {
   int i, j;
   
   for(i = 2; i<100; i++) {
      for(j = 2; j <= (i/j); j++)
         if(!(i%j)) break; // if factor found, not prime
         if(j > (i/j)) cout << i << " is prime\n";
   }
   
   return 0;
}


RocketCountdown.cpp:

#include <iostream>
using namespace std;
int main ()
{
  int n = 10;
  for (int i=10; i > 0 ; i--) {
    cout << n << ", ";
    --n;
  }
  cout << "liftoff!\n";
}


SimpleLoop.cpp:
#include <iostream> 
using namespace std;
int main()
{
for (int i = 0; i < 5; i++)
	cout << i << endl; 
return 0;
}


ThreeVariables.cpp:

#include <iostream>
using namespace std;
int main ()
{   
   for( int a = 1, b = 10, c = 1 ; a < 10; a = a + 1, b = b - 1, c = c * 2 )
   {
       cout << "value of a: " << a << endl;
       cout << "value of b: " << b << endl;
       cout << "value of c: " << c << endl;
   } 
   return 0;
}