函数名: textwidth 
 功  能: 返回以像素为单位的字符串宽度 
 用  法: #include <graphics.h> 
         int far textwidth(char far *textstring); 
 程序例:
#include <graphics.h> 
 #include <stdlib.h> 
 #include <stdio.h> 
 #include <conio.h>
int main(void) 
 { 
    /* request auto detection */ 
    int gdriver = DETECT, gmode, errorcode; 
    int x = 0, y = 0; 
    int i; 
    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 */ 
    }
   y = getmaxy() / 2;
   settextjustify(LEFT_TEXT, CENTER_TEXT); 
    for (i=1; i<11; i++) 
    { 
       /* select the text style, direction, and size */ 
       settextstyle(TRIPLEX_FONT, HORIZ_DIR, i);
      /* create a message string */ 
       sprintf(msg, "Size: %d", i);
      /* output the message */ 
       outtextxy(x, y, msg);
      /* advance to the end of the text */ 
       x += textwidth(msg); 
    }
   /* clean up */ 
    getch(); 
    closegraph(); 
    return 0; 
 }