（笔试题）输出这段代码的结果（关于进制位的代码）

#include
int main()
{
  char a=-1;
  signed char b=-1;
  unsigned char c=-1;
  printf("a=%d,b=%d,c=%d",a,b,c);
  return 0;
}

#include
int main()
{
  //10000000000000000000000000000001
  //11111111111111111111111111111110
  //11111111111111111111111111111111
  
  char a=-1;
  //char 11111111 %d的打印。高位补位和符号为一致，这里的符号位是1，进行整型提升
  //11111111111111111111111111111111补码，所以原码还是-1
  signed char b=-1;
  //char 11111111
  unsigned char c=-1;
  //无符号char 11111111，进行整型提升
  //00000000000000000000000011111111，成为了正数 原码、反码、补码相同
  //打印出来的是255
  
  printf("a=%d,b=%d,c=%d",a,b,c);//%d整型
  return 0;
}