OSX Buil failure with error:"Undefined symbol: matplot::gca()"

[re-tart]

I just installed matplot++ (on my osx10.15.4) and tried a simple plot(x,y) and ended up with build failure with error

"Undefined symbol: matplot::gca()

,then i tried using gca() directly and ended up with exactly the same error.

I have included my <matplot/matplot.h> header file as instructed , now i have no clue what could be the cause of this error.

Any help would be appreciated

[alandefreitas]

You need to link the library.

[re-tart]

shoot.thanks.

[re-tart]

ehh.and where can i get the name of the library? or can you just tell me? as you can tell, i am a newbie in coding hhhhh

[re-tart]

so now i found and linked libmatplot.dylib,but now i got a runtime error:sh: gnuplot: command not found. how can i fix this problem?

[re-tart]

problem solved!!thanks anyway