Examples on different ways to calculate the LCM (Lowest Common Multiple) of two integers using loops and decision making statements.

To understand this example, you should have the knowledge of the following C++ programming topics:

LCM of two integers `a` and `b` is the smallest positive integer that is divisible by both `a` and `b`.

```
#include <iostream>
using namespace std;
int main()
{
int n1, n2, max;
cout << "Enter two numbers: ";
cin >> n1 >> n2;
// maximum value between n1 and n2 is stored in max
max = (n1 > n2) ? n1 : n2;
do
{
if (max % n1 == 0 && max % n2 == 0)
{
cout << "LCM = " << max;
break;
}
else
++max;
} while (true);
return 0;
}
```

**Output**

Enter two numbers: 12 18 LCM = 36

In above program, user is asked to integer two integers `n1` and `n2` and largest of those two numbers is stored in `max`.

It is checked whether `max` is divisible by `n1` and `n2`, if it's divisible by both numbers, `max `(which contains LCM) is printed and loop is terminated.

If not, value of `max` is incremented by 1 and same process goes on until `max `is divisible by both `n1` and `n2`.

The LCM of two numbers is given by:

LCM = (n1 * n2) / HCF

Visit this page to learn: How to compute HCF in C++?

```
#include <iostream>
using namespace std;
int main()
{
int n1, n2, hcf, temp, lcm;
cout << "Enter two numbers: ";
cin >> n1 >> n2;
hcf = n1;
temp = n2;
while(hcf != temp)
{
if(hcf > temp)
hcf -= temp;
else
temp -= hcf;
}
lcm = (n1 * n2) / hcf;
cout << "LCM = " << lcm;
return 0;
}
```