#include<stdio.h>
#include<graphics.h>
main()
{
 int gdriver=DETECT,gmode;
 char c='a',s[20];
 inigraph(&gdriver,&gmode,"c:\\turboc2");
 setbkcolor(7);
 setcolor(4);
 settextstyle(1,0,2);
 sprintf(s,"%c",c); /*没有输出*/
 getch();
 closegraph();
}

我知道了
sprintf():
后面加一句输出语句

SPRINTF

see this page:
http://
sprintf详解

#include<stdio.h>
#include<graphics.h>
main()
{
int gdriver=DETECT,gmode;
char c='a',s[20];
initgraph(&gdriver,&gmode,"c:\TC200");
setbkcolor(5);
setcolor(20);
settextstyle(1,0,2);
sprintf(s,"%c",c); /*没有输出*/
 printf("%c",s[0]);
getch();
closegraph();
}