Executing c graphics programs in Terminal

the following prgm has been written in the vi editor...it has been named hello.cpp

#include<iostream>
#include<graphics>
int main(void)
{
int gd = DETECT, gm;
initgraph(&gd, &gm, "");
line(0, 0, 100, 100);
closegraph();
}

the errors are as follows:

g++ hello.cpp -o hello

hello.cpp:2:19: error: graphics: No such file or directory
hello.cpp: In function 'int main()':
hello.cpp:5: error: 'DETECT' was not declared in this scope
hello.cpp:6: error: 'initgraph' was not declared in this scope
hello.cpp:7: error: 'line' was not declared in this scope
hello.cpp:8: error: 'closegraph' was not declared in this scope

kindly assist...