如何画一个循环的东西（FLTK / C ++）？

Question

I have a problem drawing more than one line, it only show one line i use

void fl_push_clip(int x, int y, int w, int h);

but nothing seems to work

I try something like this

for (int i = 1; i < 10; i++) {
        int x = 10 * i, y = 10 * i;
        int w = 70 * i, h = 70 * i;
        void fl_push_clip(int x, int y, int w, int h);

        cout << "TEST" << endl;
    }

i use cout to see if the for works

#include <FL/Fl.H>
#include <FL/Fl_Widget.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Input.H>
#include <FL/Fl_Int_Input.H>
#include <FL/Fl_Button.H>
#include <FL/Fl_Color_Chooser.H>

int main(int argc, char ** argv)
{
    int width = 90, height = 80;
    int rowmax = 4, colmax = 7;

    window = new Fl_Window(colmax * width + 20, rowmax * height + 240);
    window->color(FL_DARK_GREEN);

    Fl_Int_Input input = new Fl_Int_Input(140, rowmax * height + 20, colmax * width - 160, 20, "test1");
    input->labelfont(FL_BOLD + FL_ITALIC);

    for (int i = 1; i < 10; i++) {
        int x = 10 * i, y = 10 * i;
        int w = 70 * i, h = 70 * i;
        void fl_push_clip(int x, int y, int w, int h);

        cout << "TEST" << endl;
    }   
    window->end();
    window->show(argc, argv);
    return Fl::run();
}

I expect to see if the for is useful to draw multiple shapes or find an alternative to do the same

Answer 1

The code here is a declaration: it does not call the code at all

for (int i = 1; i < 10; i++) {
    int x = 10 * i, y = 10 * i;
    int w = 70 * i, h = 70 * i;
    void fl_push_clip(int x, int y, int w, int h); // This is a declaration

    cout << "TEST" << endl;
}

If you wish to call the routine use

for (int i = 1; i < 10; i++) {
    int x = 10 * i, y = 10 * i;
    int w = 70 * i, h = 70 * i;
    fl_push_clip(x, y, w, h); // This is a call

    cout << "TEST" << endl;
}

Do you have std namespace defined somewhere?