Constructor Statements

[UofFprogrammer]

Hello,
I was (once again) experimenting with some CPP code using constructors. I defined a constuctors 2 different ways. I believe the end result is the same, but what causes the difference in run-time for the program. Specifically, the first code took my computer 9 seconds to run, while the second code took 15 seconds, a 66% difference. I repeated the "experiment" several times and got the same result. I'm guessing that the first code doesn't have to create objects a,b,c and then initialize them to a value, but it does both at the same time? (i.e.) they are created with the values given.
Can you guys explain the difference? Is the first more "efficient"? Are there any downsides to writing a constructor like this?

#include<iostream>
 
using namespace std;
class trial{
    private:
    double a,b,c;
    public:
    trial();
    void display();
};
trial::trial()
: a(5), b(9) , c(10)
{ }
void trial::display(){
    cout<<a<<' '<<b<<' '<<c;
}
int main(){
    for(unsigned long long int i=0; i<990000000; i++){
        trial f;
 
    }
return 0;
}

The Second code is

#include<iostream>
 
using namespace std;
class trial{
    private:
    double a,b,c;
    public:
    trial();
    void display();
};
trial::trial()
{a=5;
b=0;
c=10; }
void trial::display(){
    cout<<a<<' '<<b<<' '<<c;
}
int main(){
    for(unsigned long long int i=0; i<990000000; i++){
        trial f;
 
    }
return 0;
}
 

Once again, Thanks for assuaging my curiosity.

[weaknessforcats]

Can you guys explain the difference? Is the first more "efficient"? Are there any downsides to writing a constructor like this?

You just did. And Yes. And no.

As to the third question, that could involve constructor calls on ther members. That means there coulkd be exceptions. You might want to use a function-try block in that case. But as long as you use built-in types what you have will work fine.