char[ ]初始化时占用字节数

int main(int argc, char *argv[])  
{  
    char a[] = "12"; //带字符串结束字符'\0'  
    printf("a字节数为：%d\n", sizeof(a));  
  
    char b[] = { '1', '2', '3' };  
    printf("b字节数为：%d\n", sizeof(b));  
  
    system("pause");  
    return 0;  
}  

运行结果: