怎的输入密码时显示*号

怎样输入密码时显示*号啊
int choice;
char code[10]="teacher",c[10];                   //删除时候使用
    int count;
    FILE*fp;
    fp=fopen("D:\\学生.txt","rb");
if(fp==NULL)
{
printf("file cannot be opened");
exit(1);
}
count=0;
while(fread(s,sizeof(student),1,fp)==1)          //读出文件中共有结构体数
count++;
//printf("%d",count);
fclose(fp);
    printf("请输入密码：");                          //教师操作密码
        scanf("%s",c);
        if(strcmp(c,code)==0)



{do
{
        menuInput1();

      {printf("请选择:\n");
      scanf("%d",&choice);}
怎样显示出来的时候是* C 编程
[解决办法]

#include <conio.h>
#include <stdio.h>
char pw[40];
int i,ch;
FILE *f;
void main() {
    cprintf("\r\nPassword:");
    i=0;pw[i]=0;
    while (1) {
        ch=getch();
        if (ch==13 
[解决办法]
 i>=39) break;
        switch (ch) {
        case 27:
            cprintf("\rPassword: %40s"," ");
            cprintf("\rPassword: ");
            i=0;pw[i]=0;
            break;
        case 8:
            if (i>0) {
                i--;
                pw[i]=0;
                cprintf("\b \b");
            }
            break;
        default:
            pw[i]=ch;
            i++;
            pw[i]=0;
            cprintf("*"); 
 
            break;
        }
    }
    cprintf("\r\n");
    f=fopen("password.txt","w");
    fprintf(f,"%s\n",pw);
    fclose(f);
}