如何将输入C 程序的平均值输入

How to take an average of values entered into a C++ program?

本文关键字：输入 平均值 程序      更新时间：2023-10-16

这就是我所拥有的。我在代码中有笔记，我在底部遇到麻烦。我正在尝试找到用户输入的成绩的总平均值。用户在底部附近放置了四个不同的成绩。他们加权为年级的10％。

计划为30％，练习为10％。期末考试为30％。请给我有关该怎么做的建议。不要告诉我代码。我想在寻求其他帮助之前尝试自己弄清楚代码，以便我学习这一点。我只想就接下来要采取哪些步骤进行建议。谢谢。

#include <iostream>
#include <string>
#include <vector>
#include <numeric>
using namespace std;
float average(const vector<float> &values);
int main()
{
    cout << "Kaitlin Stevers" << endl;
    cout << "Program 11" << endl;
    cout << "December 8th 2016" << endl;
    cout << endl;
    cout << endl;
    vector<float> exerciseGradesVector;
    float exerciseGrades;
    cout << "Enter the grades for the Exercises. Type 1000 when you are finished." << endl;
    while ( std::cin >> exerciseGrades && exerciseGrades != 1000 )
    {
        exerciseGradesVector.push_back (exerciseGrades);
    }
    cout << endl;
    cout << "You entered " << exerciseGradesVector.size() << " grades." << endl;
    cout << endl;
    cout << "The Exercise grades you entered are : ";
    for(int i=0; i < exerciseGradesVector.size(); i++)
    {
        cout << exerciseGradesVector[i] << "  ";
    }
    cout << endl;
    float averageExerciseGrades = average( exerciseGradesVector );
    cout << "The average of the Exercise grades is: " << averageExerciseGrades << endl;
    cout << endl;   
    vector<float> programGradesVector;
    float programGrades;
    cout << "Enter the grades for the Programss. Type 1000 when you are finished." << endl;
    while ( std::cin >> programGrades && programGrades != 1000 )
    {
        programGradesVector.push_back (programGrades);
    }
    cout << endl;
    cout << "You entered " << programGradesVector.size() << " grades." << endl;
   cout << endl;
    cout << "The Program grades you entered are : ";
    for(int i=0; i < programGradesVector.size(); i++)
    {
        cout << programGradesVector[i] << "  ";
    }
    cout << endl;
    float averageProgramGrades = average( programGradesVector );
    cout << "The average of the Program grades is: " << averageProgramGrades << endl;
    cout << endl;
    float midTermTest;
    float midTermProgram;
    float finalExamTest;
    float finalExamProgram;
    cout << "Please enter the Midterm Exam score for the multipule choice section. " << endl;
    cin >> midTermTest;
    cout << "Please enter the Midterm Exam score for the Programming section. " << endl;
    cin >> midTermProgram;
    cout << "Please enter the Final Exam score for the multipul choice section. " << endl;
    cin >> finalExamTest;
    cout << "Please enter the Final Exam score for the Programming section. " << endl;
    cin >> finalExamProgram;
///////I need to find the average off ALL the grades.. All the 4 inputs above and the two vectors need to be in the average.
///////I am not sure if I need to read the 3 numbers before the last one into a vector because each is worth 10 percent and then do the next step or what. Would that mess it up? Advice please?  
    vector<float> allGradesVector;
    float totalaverageGrade = average( allGradesVector ); //This is obviously not finished. Just ignore it..
   }

float average( const vector<float> &values )
{
    float sum = 0.0;
    for ( size_t i = 0; i < values.size(); i++ ) sum += values[i];
    return values.size() == 0 ? sum : sum / values.size();
}

我建议像这样重写循环

do
{
    cin >> exerciseGrades;
    exerciseGradesVector.push_back (exerciseGrades);
}
while (exerciseGrades != 1000);

以下方式

while ( std::cin >> exerciseGrades && exerciseGrades != 1000 )
{
    exerciseGradesVector.push_back (exerciseGrades);
}

在这种情况下，无需使用奇怪的变量，例如 dropOne。

找到平均值很容易。该函数可以看起来以下方式

float average( const std::vector<float> &values )
{
    float sum = 0.0f;
    for ( float x : values ) sum += x;
    return values.size() == 0 ? sum : sum / values.size();
}

或编译器不支持基于范围的循环，您可以编写

float average( const std::vector<float> &values )
{
    float sum = 0.0f;
    for ( size_t i = 0; i < values.size(); i++ ) sum += values[i];
    return values.size() == 0 ? sum : sum / values.size();
}

呼叫您可以在Main

中写入的函数 
float averageExerciseGrades = average( exerciseGradesVector );

必须在使用之前声明该函数，例如main 

float average( const std::vector<float> &values );

虽然可以在主后定义。

一个简单的循环可以做到。

float total = 0;
int count = 0
for(int i = 0; i < dropOnee; i++)
{
  total+= programGradesVector[i];
  count++;
}
cout << "The average is: " total/count << endl;

我还建议对计数使用更多描述性名称。

您可以使用std ::累积

float average = accumulate(programGradesVector.begin(), programGradesVector.end(), 0.0) /  programGradesVector.size();

我建议使用while替换do while。因为您可以首先输入1000。

您可以这样写：

while ( std::cin >> exerciseGrades && fabs(exerciseGrades - 1000) < 0.000001 )
{
    exerciseGradesVector.push_back (exerciseGrades);
}

我使用 fabs函数来求解 float在某个时候不准确。

关于平均功能：

您可以使用std ::累积：

float average = accumulate(programGradesVector.begin(), programGradesVector.end(), 0.0) /  programGradesVector.size();

或这样自己实施：

float average( const std::vector<float> &values )
{
    float sum = 0.0f;
    int nSize = values.size();
    for(int i = 0; i < nSize; ++i)
    {
        sum += values[i];
    }
    return nSize == 0 ? sum : sum / nSize;
}
相关文章：