不会为循环周期添加从其他函数获得的内容 [英] Won't add what it got from the other function each for loop cycle

问题描述

  #include   <   stdio.h  >  
  
  //  将字母等级转换为数字的功能 
  float  GradePoints（ char 等级）
 {
  float  gP; 
 
 开关（等级）
 {
 案例 '  A'：
  case  '  a'：
 gP =  4 。 0 ; 
  break ; 
 
  case  '  B' ：
  case  '  b '：
 gP =  3 。 0 ; 
  break ; 
 
  case  '  C' ：
  case  '  c '：
 gP =  2 。 0 ; 
  break ; 
 
  case  '  D' ：
  case  '  d '：
 gP =  1 。 0 ; 
  break ; 
 
  case  '  F' ：
  case  '  f '：
 gP =  0 。 0 ; 
  break ; 
} 
 
  return  gP; 
} 
 
 
  //  计算平均成绩点的函数 
  float  Gpa（ char  grade []， char  hours []， int  arrLength）
 {
  //   gradepoint *课堂上的时间 
  float  totalGpHours =  0 ; 
  //  课堂上的时间 
  float  totalHours =  0 ; 
  //  最终成绩点平均值 
  float  gradePointAverage; 
  int  i; 
 
  for （i =  0 ; i< arrLength; ++ i ）
 {
  //  在每个班级中添加用户输入时间以获得课堂上的总时间。这是分母 
 totalHours = hours [i] + totalHours; 
  //  将该课程的班级和成绩等级中的小时数相乘，并将产品添加到totalGpHours。这是分子 
 totalGpHours = totalGpHours +（GradePoints（grades [i]）* hours [i]）; 
 
} 
 
  //  计算平均成绩点 
 gradePointAverage = totalGpHours / totalHours; 
 
  return  gradePointAverage; 
 
} 
 
 
 
  int  main（）
 {
  //  因为null  
  char 成绩[ 6 ]; 
  int  classTime [ 5 ]; 
  int  i; 
 
  //  向用户询问字母等级 
 printf（< span class =code-string> 请输入您收到的字母等级（大写字母，无空格）：\ n） ; 
  //  得到输入加一个数组成绩 
 fgets（成绩，  6 ，stdin）; 
 
  //  询问用户每个班级的时间 
 printf （ 请输入您在每门课程中花费的时间（以小时为单位））; 
 
  for （i =  0 ; i<  5 ; ++ i）
 {
  //  添加一个给i，这样对于用户来说看起来很正常，你不会从0开始 
 printf（  \ n课程％d：，i +  1 ）; 
 scanf（ ％d，& classTime [i]）; 
} 
 
 
 printf（  \ n）; 
 printf（ 您的平均成绩是：％f\\\
\ n ，Gpa（成绩，classTime， 5 ））; 
 
 
 getchar（）; 
 
  return   0 ; 
} 

我的尝试：



一切。如果我得到4个第一个周期和4个下一个周期，它应该添加它们，但它不会。

解决方案

你应该学会尽快使用调试器尽可能。而不是猜测你的代码在做什么，现在是时候看到你的代码执行并确保它完成你期望的。



调试器允许你跟踪执行逐行检查变量，你会看到它有一个停止做你期望的点。

调试器 - 维基百科，免费的百科全书 [ ^ ]

掌握Visual Studio 2010中的调试 - A初学者指南 [ ^ ]



调试器在这里向您展示您的代码正在做什么，您的任务是与它应该做什么进行比较。 />
当代码不做ex的时候你接近一个bug。

我会告诉你相关的一行：

 float Gpa（char grade []， char hours []，int arrLength）
 // ... 
 char grade [6]; 
 int classTime [5]; 
 // ... 
 Gpa（成绩，班级时间，5）

你现在看到了吗？

Gpa 函数需要三个参数 char [] ， char [] 和 int 。但是你传递 char [] ， int [] 和 int 。



编译器也应该识别这一点并抛出警告或错误。如果你没有得到这样的编译器消息，请增加编译器的警告级别（例如，使用-Wall with GCC和/ Wall with MS compilers）。



要解决这会将您的 Gpa 函数更改为

 float Gpa（char grades []，int hours []，int arrLength）

#include <stdio.h>

//function to convert letter grade into a number
float GradePoints(char grade)
{
	float gP;

	switch (grade)
	{
	case 'A':
	case 'a':
		gP = 4.0;
		break;

	case 'B':
	case 'b':
		gP = 3.0;
		break;

	case 'C':
	case 'c':
		gP = 2.0;
		break;

	case 'D':
	case 'd':
		gP = 1.0;
		break;

	case 'F':
	case 'f':
		gP = 0.0;
		break;
	}

	return gP;
}


//function to calculate grade point average
float Gpa(char grades[], char hours[], int arrLength)
{
	//gradepoint * time in class
	float totalGpHours = 0;
	//time in class
	float totalHours = 0;
	//final grade point average 
	float gradePointAverage;
	int i;

	for (i = 0; i < arrLength; ++i)
	{
		//add the user input time in each class to get total time in class. this is the denominator
		totalHours = hours[i] + totalHours;
		//multiplies hours in class and number grade from that class and adds the product to totalGpHours. this is the numerator
		totalGpHours = totalGpHours + (GradePoints(grades[i]) * hours[i]);

	}

	//calculate grade point average
	gradePointAverage = totalGpHours / totalHours;

	return gradePointAverage;

}



int main()
{
	//add one more element to the array because of the null
	char grades[6];
	int classTime[5];
	int i;

	//Ask user for letter grades
	printf("Please enter the letter grades you received (upper-case letters, no spaces):\n");
	//gets input plus one for the array grades
	fgets(grades, 6, stdin);

	//Ask user for time in each class
	printf("Please enter the time you spent in each course(in hours)");

	for (i = 0; i < 5; ++i)
	{
		//add one to i so it looks normal for the user and you don't start at course 0
		printf("\n Course %d: ", i + 1);
		scanf("%d", &classTime[i]);
	}


	printf("\n");
	printf("Your grade point average is: %f\n\n", Gpa(grades, classTime, 5));


	getchar();

	return 0;
}

What I have tried:

everything. if i got 4 the first cycle and 4 the next, it's supposed to add them, but it doesn't.

解决方案

You should learn to use the debugger as soon as possible. Rather than guessing what your code is doing, It is time to see your code executing and ensuring that it does what you expect.

The debugger allow you to follow the execution line by line, inspect variables and you will see that there is a point where it stop doing what you expect.
Debugger - Wikipedia, the free encyclopedia[^]
Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]

The debugger is here to show you what your code is doing and your task is to compare with what it should do.
When the code don't do what is expected, you are close to a bug.

I will show you the relevant lines:

float Gpa(char grades[], char hours[], int arrLength)
// ...
char grades[6];
int classTime[5];
// ...
Gpa(grades, classTime, 5)

Did you see it now?
The Gpa function expects three parameters of type char[], char[], and int. But you are passing char[], int[], and int.

The compiler should recognize this too and throw out a warning or error. If you did not got such compiler message, increase the warning level of the compiler (e.g. by using -Wall with GCC and /Wall with MS compilers).

To solve this change your Gpa function to

float Gpa(char grades[], int hours[], int arrLength)

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