一些简单的逻辑问题并打印 C++ HouseWindowsLab

Question

请帮忙。这个简单的程序假设计算用户输入他们想要的每所房子的数量。乘以每所房子增加的窗户。并为备件总数应用 1% 的窗口。为什么备件不工作？

/*************************************
* PROGRAM: WindowCalculator
* AUTHOR: Matthew Nickles
* DATE: 9/6/2018
* NOTES: This is for educational purposes, the program calculates
* how many windows for each house plan a city builder would get.
**************************************/

/* PREPROCESSOR COMMANDS */
#include <stdio.h>


/* MAIN PROCESSING CONTROL */
int main()
{
/* VARIABLE DECLARATIONS */
int MontgomeryHouses; /*20 Windows per a house*/
int KetteringHouses; /*15 Windows per a house*/
int SaxonHouses; /*12 Windows per a house*/
int TotalWindows; /*Total calculation of all windows*/
int SpareWindows; /*How many spare windows if you wanted 1% of total*/ 

/* WINDOWS PER HOUSE ALGORITHM */
printf("\n How many Montgomery Houses do you wish to build? They have 20             windows. ");
scanf("\n%d", &MontgomeryHouses);
fflush(stdin);

printf("\n How many Kettering Houses do you wish to build? They have 15 windows. ");
scanf("\n%d", &KetteringHouses);
fflush(stdin);

printf("\n How many Saxon Houses do you wish to build? They have 12 windows. ");
scanf("\n%d", &SaxonHouses);
fflush(stdin);

/* CALCULATE TOTAL WINDOWS*/
TotalWindows = (MontgomeryHouses * 20) + (KetteringHouses * 15)
        + (SaxonHouses * 12);
SpareWindows = TotalWindows * 0.01;
/* DISPLAY OUTPUT*/
printf("The spare windows needed &d are windows.\n",SpareWindows);
fflush(stdin);  
printf("\nThe total amount of windows needed for all houses are %d windows.\n",TotalWindows);
fflush(stdin);



return 0;
}
/* END OF PROGRAM */

Answer 1

你的逻辑完全没问题。这只是一个微小的语法错误。 在这一行：

printf("The spare windows needed &d are windows.\n",SpareWindows);

&d 应替换为 %d。

我认为你只是忽略了它，因为其他部分都很完美。

Answer 2

您的问题是整数不能在点后有数字。例如：SpareWindows = 50.43，但是因为您将其声明为 int，所以它会被截断为 50。您可能想改用floats，例如：

/* VARIABLE DECLARATIONS */
int MontgomeryHouses; /*20 Windows per a house*/
int KetteringHouses; /*15 Windows per a house*/
int SaxonHouses; /*12 Windows per a house*/
int TotalWindows; /*Total calculation of all windows*/
float SpareWindows; /*How many spare windows if you wanted 1% of total*/ 

由于您的窗口总数始终可以只是一个“完整”数字，因此将它们声明为 ints 完全没问题。但是当移动到一个百分比时，比如SpareWindows，你必须使用floats。你可能想看看here

Answer 3

试试这个代码：

#include <stdio.h>


/* MAIN PROCESSING CONTROL */
int main()
{
/* VARIABLE DECLARATIONS */
int MontgomeryHouses; /*20 Windows per a house*/
int KetteringHouses; /*15 Windows per a house*/
int SaxonHouses; /*12 Windows per a house*/
int TotalWindows; /*Total calculation of all windows*/
float SpareWindows; /*How many spare windows if you wanted 1% of total*/ 

/* WINDOWS PER HOUSE ALGORITHM */
printf("\n How many Montgomery Houses do you wish to build? They have 20             windows. ");
scanf("\n%d", &MontgomeryHouses);
fflush(stdin);

printf("\n How many Kettering Houses do you wish to build? They have 15 windows. ");
scanf("\n%d", &KetteringHouses);
fflush(stdin);

printf("\n How many Saxon Houses do you wish to build? They have 12 windows. ");
scanf("\n%d", &SaxonHouses);
fflush(stdin);

/* CALCULATE TOTAL WINDOWS*/
TotalWindows = (MontgomeryHouses * 20) + (KetteringHouses * 15)
        + (SaxonHouses * 12);
SpareWindows = (float)TotalWindows * 0.01; //Used Explicit type conversion to float
/* DISPLAY OUTPUT*/
printf("The spare windows needed %f are windows.\n",SpareWindows);
fflush(stdin);  
printf("\nThe total amount of windows needed for all houses are %d windows.\n",TotalWindows);
fflush(stdin);



return 0;
}
/* END OF PROGRAM */

实际上问题在于，当您尝试将整数乘以小数时，输出会转换为整数，因此我们必须明确指定该值应为浮点数。 希望有效。

Answer 4

您的程序中存在多个问题。

让我开始一一指出。

考虑：scanf("\n%d", &MontgomeryHouses);

为什么你在scanf() 中使用了'\n'？输入时无需在此处使用'\n'。

我看到你在你的程序中使用了fflush(stdin); 5 次。停止在 C 程序中使用 fflush(stdin)。 fflush() 函数只能用于输出流。阅读Standard streams 了解更多信息。在 C 和 C++ 中使用 fflush(stdin) 是 Undefined behavior。阅读这些问题的答案What does fflush(stdin) do in C programing? 和Using fflush(stdin) 了解更多信息。

另一个问题是你写了SpareWindows = TotalWindows * 0.01;。您想在SpareWindows 变量中使用浮点值，但该变量的数据类型被定义为int 类型。它应该被定义为float SpareWindows; 所以你必须使用'%f' 格式说明符来打印这个变量的值。