my program has unexpectedly finished in QCustomPlot set name

[firsnur96]

Hi everyone. I have a struct which i show you in below.

typedef struct list_item {
    char isim[24];
    int idx;
    int chart_no;
    int tip; // 1: float, 2: int, 3: char, 4 string
//    QLineSeries seri;
    int graph_no;
    QCPGraph *gr;
}list_item;

I want to achive QCustomPlot graphs and set a name to them. I've written this code for it

zs_gps[idx_gps].gr->setName(zs_gps[idx_gps].isim);

When i run it, my program has unexpectedly finished. When i debug i saw that in this sentence it crashed.

void QCPAbstractPlottable::setName(const QString &name)
{
  mName = name;         ///in here it crashed
}

What am i doing wrong?

[jsulm]

@firsnur96 Is gr pointer properly initialized (pointing to a valid QCPGraph instance)?

[firsnur96]

@jsulm I thought that, in this sentence i initialized

zs_gps[idx_gps].gr->setName(zs_gps[idx_gps].isim);

[Christian Ehrlicher]

@firsnur96 said in my program has unexpectedly finished in QCustomPlot set name:

zs_gps[idx_gps].gr

Where do you initialize gr ?

[jsulm]

@firsnur96 said in my program has unexpectedly finished in QCustomPlot set name:

in this sentence i initialized

I don't see any initialisation here...

[firsnur96]

@Christian-Ehrlicher

I know that, when i wrote this is already initialize.
I use the same structure in qt charts and it runs.

zs_gps[idx_gps].gr 

like

zs_gps[idx_gps].seri.setName(zs_gps[idx_gps].isim);

And i dont really understand , what should i initialize.

[jsulm]

@firsnur96 said in my program has unexpectedly finished in QCustomPlot set name:

And i dont really understand , what should i initialize.

gr
You should have this somewhere:

gr = new QCPGraph();

So, do you have it somewhere?

[firsnur96]

@jsulm I wrote it in my cpp file, it gives an error.
use of undeclared identifier gr

[jsulm]

@firsnur96 Please show the code. Also, gr is part of list_item struct, you can't use it just like "gr". The code I posted before is just to illustrate what you need to do, not the exact code...

[firsnur96]

@jsulm

zs_gps[idx_gps].gr = new QCPGraph;

[JonB]

@firsnur96

• Show you actual relevant code, rather than isolated lines at a time.
• If you get a compilation error, copy & paste the actual message here. Assuming the message includes a line number, tell us which exact line in your code that refers to by checking the line number (not guessing).
• If you get a runtime error on zs_gps[idx_gps]... something, use the debugger or a qDebug() statement on the line immediately preceding this to prove what zs_gps[idx_gps] is and the value of zs_gps[idx_gps].gr.

[jsulm]

@firsnur96 said in my program has unexpectedly finished in QCustomPlot set name:

zs_gps[idx_gps].gr = new QCPGraph;

Is this done before zs_gps[idx_gps].seri.setName(zs_gps[idx_gps].isim);?
Instead of wasting time here you could simply debug your app to find out what is happening...

[mrjj]

Hi
You should give the list_item type
a constructor that initializes its members.

Having to do it outside is a disaster waiting to happen. (IMHO)

typedef struct list_item {
  char isim[24];
  int idx;
  int chart_no;
  int tip; // 1: float, 2: int, 3: char, 4 string
  //    QLineSeries seri;
  int graph_no;
  QCPGraph* gr;
  explicit list_item() : gr(new QCPGraph ) {}  /// init
} list_item;