fgets和gets之间的区别 [英] Difference between fgets and gets

问题描述

fgets()和gets()有什么区别?

当用户仅点击输入"时，我正在尝试打破循环.它与gets()一起使用时效果很好，但是我不想使用gets(). 我尝试使用fgets()和scanf()，但结果与使用gets()的结果不同. fgets()打破循环，无论用户输入文本是什么！这是我的代码:

I am trying break my loop when the user hits just "enter". It's working well with gets(), but I don't want to use gets(). I tried with fgets() and scanf() but I don't have the same results as with gets(). fgets() breaks the loop whatever user enters in text! Here is my code :

void enter(void)
{
  int i,

  for(i=top; i<MAX; i++)
    {
      printf(".> Enter name (ENTER to quit): ");
      gets(cat[i].name);

      if(!*cat[i].name)
         break;

      printf(".> Enter Last Name: ");
      scanf("%s",cat[i].lastname);
      printf(".> Enter Phone Number: ");
      scanf("%s",cat[i].phonenum);
      printf(".> Enter e-Mail: ");
      scanf("%s",cat[i].info.mail);
      printf(".> Enter Address: ");
      scanf("%s",cat[i].info.address);
      printf("\n");
    }
  top = i;
}

推荐答案

拖放gets() 和 scanf().
创建一个帮助函数来处理和限定用户输入.

Drop gets() and scanf().
Create a helper function to handle and qualify user input.

// Helper function that strips off _potential_ \n
char *read1line(const char * prompt, char *dest, sizeof size) {
  fputs(prompt, stdout);
  char buf[100];
  *dest = '\0';
  if (fgets(buf, sizeof buf, stdin) == NULL) {
    return NULL;  // EOF or I/O error
  }
  // Remove potential \n
  size_t len = strlen(buf);
  if (len > 0 && buf[len-1] == '\n') {
    buf[--len] = `\0`;
  }
  // Line is empty or too long
  if (len == 0 || len >= size) return NULL;
  return memcpy(dest, buf, len+1);
}

void enter(void)
{
  int i;

  for(i=top; i<MAX; i++)
    {
      if (read1line(".> Enter name (ENTER to quit): ", 
          cat[i].name, sizeof cat[i].name) == NULL) break;
      if (read1line(".> Enter Last Name: ", 
          cat[i].lastname, sizeof cat[i].lastname) == NULL) break;
      if (read1line(".> Enter Phone Number: ", 
          cat[i].phonenum, sizeof cat[i].phonenum) == NULL) break;
      if (read1line(".> Enter e-Mail: ", 
          cat[i].info.mail, sizeof cat[i].info.mail) == NULL) break;
      if (read1line(".> Enter Address: ", 
          cat[i].info.address, sizeof cat[i].info.address) == NULL) break;
    }
  top = i;
}

---

fgets()和gets()的某些属性:

---

Some attributes of fgets() and gets():

fgets()读取输入并将其保存到缓冲区，直到:
1)缓冲区已满1或-
2)遇到'\n'-或-
3)流达到文件结束条件-或-
4)发生输入错误.

fgets() reads input and saves to a buffer until:
1) The buffer is 1 shy of being full - or -
2) '\n' is encountered - or -
3) The stream reaches an end-of-file condition - or -
4) An input error occurs.

gets()会执行以外的#2-#4，但不会保存'\n'.
gets()在C99中已贬值，并且不再是C11的一部分.

gets() does #2 - #4 above except it scans, but does not save a '\n'.
gets() is depreciated in C99 and no longer part of C11.

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