12天圣诞节C程序

所以我尝试自己编码圣诞节的12天。我还没有完成歌词，但我仍在设法弄清楚。但是我不明白为什么圣诞节的“第一天”会加倍并与另一份礼物一起合作，而在第12天，却没有礼物出现。我检查了交换机的情况，我猜它们似乎是正确的。我是否有可能减少我的代码以打印出完整的歌词？

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

int main() // Main Function
{
    int days, counter, num;
    //int counter = 1;  

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

    for (counter=0; counter<=12; counter++)
    {   
        // counter++;
        switch(counter)
        {
            case 1: printf("\t\tA Partridge in a Pear Tree\n");break; // Day 12
            case 2: printf("\t\tTwo Turtle Doves\n"); break;
            case 3: printf("\t\tThree French Hens\n"); break;
            case 4: printf("\t\tFour Calling Birds \n"); break;
            case 5: printf("\t\tFive Golden Rings\n"); break;
            case 6: printf("\t\tSix Geese a Laying\n"); break;
            case 7: printf("\t\tSeven Swans a Swimming\n"); break;
            case 8: printf("\t\tEight Maids a Milking\n"); break;
            case 9: printf("\t\tNine Ladies Dancing\n"); break;
            case 10: printf("\t\tTen Lords a Leaping\n"); break;
            case 11: printf("\t\tEleven Pipers Piping\n"); break;
            case 12: printf("\t\tTwelve Drummers Drumming\n"); break; // Day 1 
        }
        printf("\n\tOn the ");

        switch(counter){
            case 1:
                printf("1st");
                break;  
            case 2: 
                printf("2nd");
                break;
            case 3: 
                printf("3rd");
                break;
            case 4: 
                printf("4th");
                break;
            case 5: 
                printf("5th");
                break;      
            case 6: 
                printf("6th");
                break;
            case 7: 
                printf("7th");
                break;
            case 8: 
                printf("8th");
                break;  
            case 9: 
                printf("9th");
                break;
            case 10:    
                printf("10th");
                break;  
            case 11:    
                printf("11th");
                break;  
            case 12:    
                printf("12th");
                break;                                                                                      
                default: 
                printf("1st", num);
                break;
            }
            printf(" day of Christmas my true love sent to me\n");

        }   

        getch();
        return 0;
    }

指令说：“您的函数将仅在main（）函数中被调用，并且将不返回任何内容”。这是否意味着我将不制作更多函数？还是应该将所有代码都只放置在main函数中？还是创建单独的代码？