函数名: setbkcolor 
 功  能: 用调色板设置当前背景颜色 
 用  法: #include <graphics.h> 
         void far setbkcolor(int color); 
 程序例: 
#include <graphics.h> 
 #include <stdlib.h> 
 #include <stdio.h> 
 #include <conio.h> 
int main(void) 
 { 
    /* select a driver and mode that supports */ 
    /* multiple background colors.            */ 
    int gdriver = EGA, gmode = EGAHI, errorcode; 
    int bkcol, maxcolor, x, y; 
    char msg[80]; 
   /* initialize graphics and local variables */ 
    initgraph(&gdriver, &gmode, ""); 
   /* read result of initialization */ 
    errorcode = graphresult(); 
    if (errorcode != grOk)  /* an error occurred */ 
    { 
       printf("Graphics error: %s\n", grapherrormsg(errorcode)); 
       printf("Press any key to halt:"); 
       getch(); 
       exit(1); /* terminate with an error code */ 
    } 
   /* maximum color index supported */ 
    maxcolor = getmaxcolor(); 
   /* for centering text messages */ 
    settextjustify(CENTER_TEXT, CENTER_TEXT); 
    x = getmaxx() / 2; 
    y = getmaxy() / 2; 
   /* loop through the available colors */ 
    for (bkcol=0; bkcol<=maxcolor; bkcol++) 
    { 
       /* clear the screen */ 
       cleardevice(); 
      /* select a new background color */ 
       setbkcolor(bkcol); 
      /* output a messsage */ 
       if (bkcol == WHITE) 
   setcolor(EGA_BLUE); 
       sprintf(msg, "Background color: %d", bkcol); 
       outtextxy(x, y, msg); 
       getch(); 
    } 
   /* clean up */ 
    closegraph(); 
    return 0; 
 }