Question

我正在尝试实现一个保存系统，它允许我保存用户输入的用户在switch语句中输入的“数据包”结构的数据。输入的每条记录都存储在通过纯文本行分隔的单个文件中。它还应该提示用户他们想要命名文件，然后程序应该指示已经保存到文件的记录数，最后如果没有输入保存文件的名称，它应该返回主菜单。 / p>

从底部的void save函数中可以看到，我试图实现这个保存系统，但是当我运行程序并选择S将记录保存到文件时，它只是在输入名称后崩溃了程序为文件名。所以如果有人能帮助我，那就太好了。

struct packet{
    int source;
    int destination;
    int type;               // Varibles for the structure
    int port;
    char data[50];
    char * filename;
};

void save(int, struct packet*); //function to save the records stored to a file
int main ()
{
struct packet s[50];         //Array for structure input
char choice;
int NetworkPacket = 0, ii = 0;
int recordCount = 0;
struct packet *records;
struct packet *temp;
records = malloc(sizeof(struct packet));

选择保存文件的案例陈述

 case 'S':
            system("cls"); //clear the screen
            save(NetworkPacket, records); //S was chosen so use the Save function
 break;

保存功能

 void save(int rCount, struct packet *records){
  FILE *recordFile;                 //file handle
  char fileName[30] = { '\0'};      //string to store the file name
  int i;

  puts("Enter a filename to save the records :");   //ask the user for the filename
  scanf("%s", fileName);                            //store the filename: data input should be checked
                                                    //here in your program

  //try and open the file for writing and react accordingly if there is a problem
  if((recordFile = fopen(fileName,"w"))==NULL){
      printf("Couldn't open the file: %s\n",fileName);
      exit(1);
  }
  else{ //the file opened so print the records array of packets to it
      for(i=0;i<rCount;i++){
          fprintf(recordFile,"%04d %04d %04d %04d %s\n",
                  records[i].source,
                  records[i].destination,
                  records[i].type,
                  records[i].port,
                  records[i].port,
                  records[i].data);
      }
      fclose(recordFile);   //close the file
  }

}

Answer 1

格式字符串中还需要一个％d修饰符 - 有五个整数但只有四个％s

fprintf(recordFile,"%04d %04d %04d %04d %04d %s\n",
                                        ^^^^

将数据结构保存到文本文件

1 个答案: