C语言 非打印字符

#include<stdio.h>

int main(void)
{
char ch;
ch = 7;
int count = 20;
/*printf("%c",ch);
printf("\007");
printf("\a");
printf("\7");
printf("\x7");
printf("%c",'\7');*/
printf("Hello\073\n");
printf("%c\n",10);
printf("Hello\070\n");
printf("%c\n",7);
printf("Hello\071\n");
printf("%c\n",8);
printf("Hello\072\n");
printf("%c\n",9);
}