Question

我试图打印包含两个字符串的结构数组。但是我的打印功能不会打印多个数组的两个索引。我不确定为什么，因为在我看来逻辑是正确的。

这是主要功能

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// =======================================

(function() {
  // then a lot more

这是我打印库函数

      const int MAX_LENGTH = 1024;

      typedef struct song
      {
          char songName[MAX_LENGTH];
          char artist[MAX_LENGTH];
      } Song;


      void getStringFromUserInput(char s[], int maxStrLength);
      void printMusicLibrary(Song library[], int librarySize);


      void printMusicLibraryTitle(void);
      void printMusicLibrary (Song library[], int librarySize);
      void printMusicLibraryEmpty(void);


      int main(void) {

      // Announce the start of the program
      printf("%s", "Personal Music Library.\n\n");
      printf("%s", "Commands are I (insert), S (sort by artist),\n"
       "P (print), Q (quit).\n");

      char response;
      char input[MAX_LENGTH + 1];
      int index = 0;

      do {
          printf("\nCommand?: ");
          getStringFromUserInput(input, MAX_LENGTH);

          // Response is the first character entered by user.
          // Convert to uppercase to simplify later comparisons.
          response = toupper(input[0]);

          const int MAX_LIBRARY_SIZE = 100;
          Song Library[MAX_LIBRARY_SIZE];

          if (response == 'I') {

               printf("Song name: ");
               getStringFromUserInput(Library[index].songName, MAX_LENGTH);


                printf("Artist: ");
                getStringFromUserInput(Library[index].artist, MAX_LENGTH);

                index++;


          }

          else if (response == 'P') {
               // Print the music library.
              int firstIndex = 0;

              if (Library[firstIndex].songName[firstIndex] == '\0') {
              printMusicLibraryEmpty();
              } else {
                  printMusicLibraryTitle();
                  printMusicLibrary(Library, MAX_LIBRARY_SIZE);
              }

Answer 1

我认为问题是由于在for循环外设置了empty = true，然后检查(!empty)，它将评估为false。令我惊讶的是它是如何打印两个指数的。您应该设置empty = false，因为您在函数调用之前已经检查了第一个索引。

Answer 2

逻辑有两种终止列表的方法：1）如果达到条目数，或2）如果任何条目为空。

我预计第二个条件是在您预期之前停止列表。可能这个阵列没有像预期的那样构建（我没有看到那个部分），或者有些东西正在覆盖早期或中间入口。

Answer 3

你的定义为：

  typedef struct song
  {
      char songName[MAX_LENGTH];
      char artist[MAX_LENGTH];
  }Song;

后来，你写了if (library[i].songName[i] != '\0')这真的很奇怪：你为什么要用与lib相同的索引索引songname字符串？所以我自然希望你的打印功能是：

    // This function will print the music library
void printMusicLibrary (Song library[], int librarySize) {

   for (int i = 0; i < librarySize; i ++) {

       printf("%s\n%s\n\n", library[i].songName,
                            library[i].artist);

   }
}

请注意，您可以通过测试library[i].songName[0] != '\0'（注意0）跳过空歌名称，但我认为最好不要将它们添加到列表中（空歌名称是否为sens？）

（如果你决定解决这个问题，请注意你有另一个可疑的地方：if (Library[firstIndex].songName[firstIndex] == '\0')具有相同的模式）

在C中打印结构数组

3 个答案: