（笔试题）这段代码输出啥

#include<stdio.h>
int main()
{
  char a=-128;
  printf("%u\n",a);
  return 0;
}

注：%u为无符号十进制整数的输出

#include<stdio.h>
int main()
{
  char a=-128;
  //10000000000000000000000010000000
  //11111111111111111111111101111111
  //11111111111111111111111110000000
  //char 10000000
  //整型提升
  //11111111111111111111111110000000-仍是补码
  //由于要打印%u，则这也是原码
  //11111111111111111111111110000000
  printf("%u\n",a);
  return 0;
}

输出：