这个简单的c程序哪有问题？

#include<reg51.h>

#include<stdio.h>

void main()                             
{
    printf("char是多少个字节？%bd字节\n",sizeof(char));

    printf("long是多少个字节？%bd字节\n ",sizeof(long));
}
EXAMPLE.C(10): 错误 C100: unprintable character 0xD7 skipped
EXAMPLE.C(10): 错误 C100: unprintable character 0xD6 skipped
EXAMPLE.C(10): 错误 C100: unprintable character 0xBD skipped
EXAMPLE.C(10): 错误 C100: unprintable character 0xDA skipped
EXAMPLE.C(10): 错误 C100: unprintable character 0xA3 skipped
EXAMPLE.C(10): 错误 C100: unprintable character 0xBF skipped
EXAMPLE.C(10): 错误 C100: unprintable character 0xCA skipped
EXAMPLE.C(10): 错误 C100: unprintable character 0xC7 skipped
example.c - 8 个错误, 0 个警告。
这是为什么？