偏離說明，有趣但內容翔實結構練習

Question

我正在爲最後的學習而努力，並擔心我在這個主題上花費太多時間，所以我想要一些輸入。這將是一種長時間的閱讀，所以我希望有人看到這一點。以下問題在本書「Beginning C，from newvice to professional」中：

「定義一個名稱爲Length的結構類型，代表長度，單位爲碼，英尺，英寸爲 ，英寸定義add（）函數這將添加兩個Length參數，並返回 作爲Length類型的總和。定義第二個函數show（），它將顯示其Length參數的值 。編寫一個使用Length類型和add（）的程序 和show（）函數將從鍵盤輸入的任意數量的長度（碼，英尺和英寸）相加，並輸出總長度。「

其中我這樣解釋：

#include "stdio.h" 
#include "stdlib.h" 
#include"string.h" 

struct length 
{ 
    float FT; 
    float YD; 
    float IN; 

}; 

struct length ReadIT(char sym[]) 
{ 
    struct length Convert; 
    float dummy; 
    printf("Enter %s\n",sym); 
    scanf("%f",&dummy); 
    Convert.FT = dummy; 
    Convert.YD = dummy/3; 
    Convert.IN = dummy*12; 
    return(Convert); 
}; 
struct length Add(struct length first, struct length second) 
{ 
    struct length total; 
    total.FT = first.FT+second.FT; 
    total.YD = first.YD + second.YD; 
    total.IN = first.IN + second.IN; 
    return total; 
}; 
void Show(struct length Convert) 
{ 
    printf("Conversions FT: %.2f\n",Convert.FT); 
    printf("Conversions YD: %.2f\n",Convert.YD); 
    printf("Conversions IN: %.2f\n",Convert.IN); 
} 
void ShowSum(struct length total) 
{ 
    printf("total FT: %.2f\n",total.FT); 
    printf("total YD: %.2f\n",total.YD); 
    printf("total IN: %.2f\n",total.IN); 
} 


int main(void) 
{ 

char cmd = 'n'; 
struct length L1,L2; 
do 
{ 

    L1 = ReadIT("Length 1"); 
    Show(L1); 
    L2 = ReadIT("Length 2"); 
    Show(L2); 
    Add(L1,L2); 
    ShowSum(Add(L1,L2));//adds up the two lengths , but how do I store them? 
    printf("Would you like to add more lengths? Type 'y' to continue");    

    scanf("%s",&cmd); 
    } 
    while(tolower(cmd)=='y'); 
    printf("The total of all lengths is : "); 

    return 0; 
} 

而且，由於該出來的書：我發現，我本來是要解釋它是這樣的：

#include <stdio.h> 
#include <ctype.h> 

#define INCHES_PER_FOOT 12 
#define FEET_PER_YARD 3 

struct Length 
{ 
    unsigned int yards; 
    unsigned int feet; 
    unsigned int inches; 
}; 

struct Length add(struct Length first, struct Length second); 
void show(struct Length length); 

int main(void) 
{ 
    char answer = 'n'; 
    struct Length length; 
    struct Length total = { 0,0,0}; 
    int i = 0; 
    do 
    { 
    printf("Enter a length in yards, feet, and inches: "); 
    scanf(" %d %d %d", &length.yards, &length.feet, &length.inches); 
    total = add(total,length); 
    printf("Do you want to enter another(y or n)?: "); 
    scanf(" %c", &answer); 
    fflush(stdin); 
    }while(tolower(answer) == 'y'); 
    printf("The total of all the lengths is: "); 
    show(total); 
    printf("\n"); 
    return 0; 
} 

struct Length add(struct Length first, struct Length second) 
{ 
    unsigned long inches = 0; 
    struct Length sum; 
    inches = first.inches + second.inches+ 
    INCHES_PER_FOOT*(first.feet+second.feet+FEET_PER_YARD* (first.yards+second.yards)); 
    sum.inches = inches%INCHES_PER_FOOT; 
    sum.feet = inches/INCHES_PER_FOOT; 
    sum.yards = sum.feet/FEET_PER_YARD; 
    sum.feet %= FEET_PER_YARD; 
    return sum; 
} 

void show(struct Length length) 
{ 
    printf("%d yards %d feet %d inches", length.yards,length.feet,length.inches);  
} 

當我看到這個答案，我的第一個想法是，「我可以做到這一點」，但它聽起來像他們想要所有這些長度分別進行每兩個單獨進行，並單獨完成個人金融時報，YD，總計。現在我癡迷於完成我的版本，但我已經打了一堵牆。有人能讓我走嗎？

Answer 1

我撞到牆了，我不能想辦法來存儲來自 第一環的總周圍，然後從下一個循環 周圍加總，採取總儲存它作爲一個變量，然後只要用戶想要，就重複這個 。

你可以做到這一點非常類似於它是如何在這本書的溶液中進行：

struct Length total = { 0, 0, 0 }, subtotal; 
… 
    ShowSum(subtotal = Add(L1, L2)); // adds up the two lengths and stores the sum 
    total = add(total, subtotal);