'a' may be used uninitialized in this function

[LuAria]

I define a variable: int a.
Then I assigned a=query.value(0).toInt(). (I used qt to connect to mysql)
Then I used a in if().
But when I built the project it warned me "'a' may be used uninitialized in this function"
What happened to my project.
Platform: Windows 10.
Qt: 5.9.1
mysql: 5.7.18

[SGaist]

Hi,

As silly as it may sound: exactly what the compiler told you.

Without the full code, here's my educated guess:

somewhere in your function:
int a;

somewhere else in the same function:
if (query.next()) {
    a = query.value(0).toInt()
}

if (a == 42) { //<< if query.next() returned false, a is still uninitialised hence the warning.
    qDebug() << "The life, the universe and the rest";
}

[Pradeep Kumar]

Hi,

When u declare the variable make sure u initialize the variables, to avoid warnings.

Thanks,

[LuAria]

@SGaist Yes, it like what you write.
The warning is :
C:\Users\Administrator\Desktop\TS\TS\buyticket.cpp:82: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
if(a<1){

[LuAria]

@Pradeep-Kumar How to initialize the variables?
Maybe I don't down that code, sorry.

[VRonin]

@LuAria said in 'a' may be used uninitialized in this function:

How to initialize the variables?

instead of int a; use int a=0; or int a{};

[LuAria]

@VRonin Thank you very much!

[Pablo J. Rogina]

@LuAria please don't forget to mark your post as solved when your problem is finally gone :-)