在DEV C+百分比计算中如何解决这个问题？

Question

我对 DEV C++ 中的百分比计算有疑问。

我想显示程序以显示百分比差异。

程序没有给出计算出的答案，而是总是给我零。

这是我的代码。

#include "stdio.h"
#include <string> 
using namespace std;
int main()
{
int book1, baht1, book2, baht2, book3, baht3, book4, baht4, ova1, book5, baht5, book6, baht6, book7, baht7, book8, baht8, ova2, Delta, Zeta;

printf("\nPlease enter monthly plan order.");
printf("\n\n\n\nPlease enter the number of 'The Devotion of Suspect X' = ");
scanf("%d", &book1);
baht1 = book1 * 185;
printf("\n\nPlease enter the number of 'Norwegian Wood' = ");
scanf("%d", &book2);
baht2 = book2 * 200;
printf("\n\nPlease enter the number of 'Beautiful World, Where Are You' = ");
scanf("%d", &book3);
baht3 = book3 * 250;
printf("\n\nPlease enter the number of 'Fascism of Love and Fantasy' = ");
scanf("%d", &book4);
baht4 = book4 * 450;
printf("\n\n_____________________________\n");
printf("\n\nPlease enter this month's total sales.");
printf("\n\n\n\nPlease enter the number of 'The Devotion of Suspect X' = ");
scanf("%d", &book5);
baht5 = book5 * 225;
printf("\n\nPlease enter the number of 'Norwegian Wood' = ");
scanf("%d", &book6);
baht6 = book6 * 325;
printf("\n\nPlease enter the number of 'Beautiful World, Where Are You' = ");
scanf("%d", &book7);
baht7 = book7 * 385;
printf("\n\nPlease enter the number of 'Fascism of Love and Fantasy' = ");
scanf("%d", &book8);
baht8 = book8 * 600;
printf("\n\n_____________________________\n");
printf("\n_____________________________\n");
printf("\n\nAlright.");
printf("\n\nLet's see your work.");
ova1 = (baht1 + baht2 + baht3 + baht4);
printf("\n\n\nBudget Price = %d Bahts\n", ova1);
ova2 = (baht5 + baht6 + baht7 + baht8);
printf("\n\nMonthly Sales Price = %d Bahts\n", ova2);
Delta = (ova2 - ova1);
    if (Delta >0)
        printf("\n\n\nYour profit : %d Bahts\n", Delta);
    else
        printf("\n\n\nYour loss : %d Bahts\n", Delta);
        
Zeta = ((Delta)/(ova1) * 100;
    if (Zeta >0)
        printf("\n\nProfit were = %f percents\n", Zeta);
    else
        printf("\n\nLoss were = %f percents\n", Zeta);
return 0;
}

我的代码有什么问题吗？

我不擅长英语和编程。

对不起，我的英语不好和任何语法错误。

感谢您的帮助（如果有的话）。

Answer 1

主要问题是数字的类型。 int 数字类型用于整数，如 3 和 99。int 类型不处理 3.5 或 0.99 等数字。如果您尝试将带小数点的数字放入int，您将丢失小数点后的详细信息。这就是为什么你得到零。例如，如果Delta=20 和ova1=50，那么您的Zeta 评估将经过以下步骤：

1. 20/50 * 100；
2. 0 * 100；因为你失去了“.4”
3. 0;

   改进它的一种方法是通过执行Zeta = 100*Delta/ova1; 来更改评估的顺序，这会：

   1. 100*20/50；
   2. 2000/50；
   3. 40；

      但这还不够，因为您仍然会丢失分数。问题的另一部分是Zeta 不应该是int；它应该是double，您需要转换（或“转换”）int 计算。

      在代码顶部附近，从 int 行中删除 Zeta 并在下面添加此行：

      double Zeta;
      

      那么计算Zeta 的行应该变成：

      Zeta = (double)100*Delta/ova1;