gráficos c ++ não funcionam “referência indefinida para…”

Question

#include<stdio.h>
#include<stdlib.h>
#include<graphics.h>
int main()
{
    int gd = DETECT, gm;
    initgraph(&gd, &gm, NULL);

    circle(50, 50, 30);

    delay(500000);
    closegraph();
    return 0;

the errors given are as follows:
    1.undefined reference to 'initgraph'       
    2.undefined reference to 'circle' 
    3.undefined reference to 'delay' 
    4.undefined reference to 'closegraph'
    currently on: -ubuntu 16.04 -codeblocks 16.01