Rainbow program in C language

#include<stdio.h> 

#include<graphics.h> 

#include<dos.h> 

  

// function for making of rainbow 

void rainbow() 

{ 

    // auto detection 

    int gdriver = DETECT,gmode; 

    int x, y, i; 

  

    // initialize graphics mode(passed three arguments to 

    // initgraph function) 

    // &gdriver is the address of gdriver variable, &gmode is 

    // the address of gmode and 

    //  "C:\\Turboc3\\BGI" is the directory path where BGI files are stored 

    initgraph(&gdriver,&gmode,"C:\\Turboc3\\BGI"); 

  

    x = getmaxx() / 2;//finding centre x-ordinate of screen 

    y = getmaxy() / 2;//finding centre y-ordinate of screen 

  

    for (i=30; i<200; i++) 

    { 

        // delay function under dos.h for holding the 

        // function for some time 

        delay(100); 

  

        // selecting  color for making of rainbow 

        setcolor(i/10); 

  

        // making of arc with fixed centre and increasing radius 

        arc(x, y, 0, 180, i-10); 

    } 

} 

// driver program 

int main() 

{ 

    rainbow(); 

    return 0; 

}