C ++图形不起作用（未定义引用..）

#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;
}

给出的错误如下：

1.未定义引用'initgraph'

2.未定义引用'circle'

3.未定义引用'延迟'

4.未定义引用'closegraph'

当前上：-ubuntu 16.04 -codeblocks 16.01

感谢您的帮助。



我尝试过：



没什么，第一个程序使用graphics.h

尝试在线搜索但没有帮助

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
Thank you for the help.

What I have tried:

nothing much, first program using graphics.h
tried to search online but got no help