The imprecision of a line count is highly influenced by code formatting style:

int
function(int a, int b, int c)
{
    // Burn the  Parthenon here.
    int culprit;
   
}
 
for(unsigned i=0; i<n; i++)
{
    // Clean your room here.
}

As opposed to:

int function(int a, int b, int c){
    int culprit; // Burn the  Parthenon here.}
for(unsigned i=0; i<n; i++){
    // Clean your room here.}

How do developers deal with this issue? It can be the difference between 120,000 lines of code and 40,000 lines of code.

I guess that if you want to trick your boss, then the former is recommended.

#include <iostream>
#include <string>

using namespace std;

int triple (int num)
{
for (num = 0; num < 12; num += 2)
{
cout << num;
}

return num;
}

int main ()
{
string name;
int digit = 0;

cout << "Enter your name: ";
getline (cin, name);

cout << "Welcome " << name << endl;

triple (digit);

return 0;
}

Yep lines of code is irrelevant. Just try to stick to the same code formatting policy agreed by your team (e.g. Google's style guides), don't start inventing your own. Apart from increasing legibility & readability, it stops a huge amount of refactoring-for-the-sake-of-readability, which developers are want to do, and is really a waste of time.

if your boss even cares about this as some kind of metric, it's time to switch job.

I mention it because some programmer blogs insinuate in their posts that it matters. It is common to read:

"My project which is a 70,000 lines of code, was finished in 2007."

"... we were dealing with a huge codebase of 5,000,000 lines of code..."

However according to a study that I heard from Arthur Griffith, it takes roughly the same amount of time to write the same amount of lines of code in different languages by the same programmer. How true that is unverifiable for now(I can't find the study.)