A simple Qt 5 plotting application
git clone https://github.com/marcoscarpetta/qt-simple-plot
cd qt-simple-plot
qmake
make
./qt-simple-plot /path/to/input-file
x1 y1 x2 y2 x3 y3 .....
x1 y1 x2 y2 x3 y3 .....
x1 y1 x2 y2 x3 y3 .....
.....
or
x1 y1
x1 y1
...
x1 y1
x2 y2 (x2 < x1)
x2 y2
...
x2 y2
x3 y3 (x3 < x2)
...