12天的聖誕節C功能的程序

Question

一個C程序，它包含一個輸出傳統聖誕歌曲「十二日聖誕節」的歌詞的功能。不要手動輸出整個歌詞。

所以我做了一個代碼，有錯誤，但我終於修好了。我的十二天聖誕歌曲循環播放效果很好。

但我有另一個問題。我的代碼是否可以作爲函數分離或解析？

指令說：「你的函數只會在main（）函數中被調用，並且不會返回任何東西。」所以我想我會使用void？以什麼方式？

#include <stdio.h> 
#include <conio.h> 

int main() // Main Function 
{ 
int days, counter, num; 

printf("\n\t\t* * * TWELVE DAYS OF CHRISTMAS * * *\n"); 
printf("\t\t_____________________________________\n\n\n"); 

for (counter=1; counter<=12; counter++) { 

printf("\tOn the "); 

switch(counter){ 
     case 1: 
      printf("1st"); 
      break; 
     case 2: 
      printf("2nd"); 
      break; 
     case 3: 
      printf("3rd"); 
      break; 
     default: 
      printf("%dth", counter); 
      break; 
    } 
printf(" day of Christmas my true love sent to me\n\n"); 

switch(counter) { 

    case 12: printf("\t\tTwelve Drummers Drumming\n\n"); 
    case 11: printf("\t\tEleven Pipers Piping\n\n"); 
    case 10: printf("\t\tTen Lords a Leaping\n\n"); 
    case 9: printf("\t\tNine Ladies Dancing\n\n"); 
    case 8: printf("\t\tEight Maids a Milking\n\n"); 
    case 7: printf("\t\tSeven Swans a Swimming\n\n"); 
    case 6: printf("\t\tSix Geese a Laying\n\n"); 
    case 5: printf("\t\tFive Golden Rings\n\n"); 
    case 4: printf("\t\tFour Calling Birds \n\n"); 
    case 3: printf("\t\tThree French Hens\n\n"); 
    case 2: printf("\t\tTwo Turtle Doves\n\n"); 
    case 1: printf("\t\t");if (counter > 1) printf("And ");printf("A Partridge in a Pear Tree\n\n"); 
    // case 1: printf("\t\tA Partridge in a Pear Tree\n\n"); 



} 

} 

getchar(); return 0; } 

試圖執行此操作，並與打印工作正常。你有任何建議，以imporove我的代碼？遇到功能問題。

Answer 1

這意味着你應該創建一個void功能做的工作：

#include <stdio.h> 

// Function Implementation 
void yourFunction(void) 
{ 
    int days, counter, num; 

    printf("\n\t\t* * * TWELVE DAYS OF CHRISTMAS * * *\n"); 
    printf("\t\t_____________________________________\n\n\n"); 

    for (counter=1; counter<=12; counter++) { 

     printf("\tOn the "); 

     switch(counter){ 
     case 1: 
      printf("1st"); 
      break; 
     case 2: 
      printf("2nd"); 
      break; 
     case 3: 
      printf("3rd"); 
      break; 
     default: 
      printf("%dth", counter); 
      break; 
     } 
     printf(" day of Christmas my true love sent to me\n\n"); 

     switch(counter) { 

     case 12: printf("\t\tTwelve Drummers Drumming\n\n"); 
     case 11: printf("\t\tEleven Pipers Piping\n\n"); 
     case 10: printf("\t\tTen Lords a Leaping\n\n"); 
     case 9: printf("\t\tNine Ladies Dancing\n\n"); 
     case 8: printf("\t\tEight Maids a Milking\n\n"); 
     case 7: printf("\t\tSeven Swans a Swimming\n\n"); 
     case 6: printf("\t\tSix Geese a Laying\n\n"); 
     case 5: printf("\t\tFive Golden Rings\n\n"); 
     case 4: printf("\t\tFour Calling Birds \n\n"); 
     case 3: printf("\t\tThree French Hens\n\n"); 
     case 2: printf("\t\tTwo Turtle Doves\n\n"); 
     case 1: printf("\t\t");if (counter > 1) printf("And ");printf("A Partridge in a Pear Tree\n\n"); 
     // case 1: printf("\t\tA Partridge in a Pear Tree\n\n"); 
     } 
    } 
} 

int main(void) 
{ 
    yourFunction(); // Call your function 

    getchar(); 
    return 0; 
} 

With live example。

Answer 2

使用void函數。

void print12DaysOfChristmas(void) 
{ 
    // Paste all your code here 
} 

int main(void) // Main Function 
{ 
    print12DaysOfChristmas(); 
    return 0; 
} 

注：

1. 關於在C函數簽名，見this answer。
2. 如果該函數未在main之前定義，則需要使用forward declaration。

Answer 3

它只是意味着所有工作必須在一個void函數，然後將其稱爲主要完成：

void doTheWork(void); // function declaration 

int main(void) 
{ 
    doTheWork(); 
    return 0; 
} 

#include <stdio.h> 
// function definition 
void doTheWork(void) 
{ 
    // put the implementation here 
} 

Answer 4

在你的程序，你需要抑制所有幻數（參見：http://en.wikipedia.org/wiki/Magic_number_%28programming%29）

而且，我優化了一下你的代碼如下：

#include <stdio.h> 
    #include <string.h> 

    #define FIRST_DAY "1st" 
    #define SECOND_DAY "2nd" 
    #define THIRD_DAY "3rd" 
    #define N_DAY  "th" 

    #define ONLY_ONE_SENTENCE 0 
    #define LAST_DAY   1 
    #define NUMBER_OF_DAYS 12 

    #define BUFFER_SIZE  5 

    #define FIRST_ANNOUNCE "\tOn the %s day of Christmas my true love sent to me\n\n" 

    const char *sentences[] = { 
     "\t\tA Partridge in a Pear Tree\n\n", 
     "\t\tAnd A Partridge in a Pear Tree\n\n", 
     "\t\tTwo Turtle Doves\n\n", 
     "\t\tThree French Hens\n\n", 
     "\t\tFour Calling Birds \n\n", 
     "\t\tFive Golden Rings\n\n", 
     "\t\tSix Geese a Laying\n\n", 
     "\t\tSeven Swans a Swimming\n\n", 
     "\t\tEight Maids a Milking\n\n", 
     "\t\tNine Ladies Dancing\n\n", 
     "\t\tTen Lords a Leaping\n\n", 
     "\t\tEleven Pipers Piping\n\n", 
     "\t\tTwelve Drummers Drumming\n\n"}; 

    void print12DaysOfChristmas(); 

    int main() { // Main Function 
     print12DaysOfChristmas(); 
     return 0; 
    } 


    void print12DaysOfChristmas() { 
     int days, counter, num, index; 
     char buffer[BUFFER_SIZE]; 
     char *day; 

     printf("\n\t\t* * * TWELVE DAYS OF CHRISTMAS * * *\n"); 
     printf("\t\t_____________________________________\n\n\n"); 

     for (counter=1; counter <= NUMBER_OF_DAYS; counter++) { 
      switch (counter) { 
       case 1: 
        day=FIRST_DAY; 
        break; 
       case 2: 
        day=SECOND_DAY; 
        break; 
       case 3: 
        day=THIRD_DAY; 
        break; 
       default: 
        snprintf(buffer, BUFFER_SIZE,"%d",counter); 
        day=strcat(buffer, N_DAY); 
        break; 
       } 

      printf(FIRST_ANNOUNCE, day); 

      for (index=counter; index > 0; index--) { 
       // If there is only one sentence 
       if (counter == LAST_DAY) { 
        printf(sentences[ONLY_ONE_SENTENCE]); 
       } else { 
        printf(sentences[index]); 
       } 
      } 
     } 

     getchar(); 
    }