一个系统的读文件片段，不理解里面的0都是啥意思

Question

void ReadFile(const char* file)
{    ComputerLink *p,*t;    FILE* fp = 0; 
        fp = fopen(file,"r");
    if (fp == 0)  
  {        printf("file open error\n");     
   return ;    }    //  
  head = (ComputerLink*)malloc(sizeof(ComputerLink));   
 head->next = 0;    
p = head;  

Answer 1

0 等价于 NULL