这道题是什么意思啊！有答案，它是怎么得出来的？请前辈们讲讲！

#include <stdio.h>            
                        
int k = 1;                                                       /*声明一个全局变量*/

/*

 * 函数声明

 */      
void fun( int);                                                  /*fun函数*/

/*main函数入口*/                             
main()   
{
    int i = 4;                                                   /*声明局部变量i，并定义为4*/
  fun(i);                                                        /*以4为参数，调用函数i*/
  printf("%d,%d\n",i,k);                                         /*输出i、k到控制台*/
}

/*

 * 函数定义

 */
void fun( int m)
{
    m += k;                                                      /*先将m加上全局变量k，然后再赋值给m*/
  k += m;                                                        /*将k加上m，然后把和赋值给k*/

 
  /** 语句块开始 **/
  {
      char k='B';                                                /*声明局部定量k，然后定义k为字符'B'*/
    printf("%d\n",k-'A');                                        /*输出k减去字符'A'的值到控制台*/
  }
  /** 语句块结束 **/

 
  printf("%d,%d\n",m,k);                                         /*输出变量m和全局变量k的值到控制台*/
}