Question

我正在尝试编写一个程序来查找加权平均值（等级等）。通过用户输入，我创建了两个相同大小的数组，一个为每个评分类别提供权重，另一个在相应类别中保存用户评分。例如，如果学生在类别1中得分为92％，其总值为总成绩的30％，则权重[1] = .3和得分[1] = .92。这样，每个类别的平均值可以通过（weights [i] * scores [i]）找到，其中i是在for循环中初始化的实例变量，以完全遍历每个数组。这里的问题在于找到累积平均值 - 我的程序被编写为复合它处理的每个平均值的值，例如我尝试过像average = average +（weights [i] * scores [i]）这样的代码来获得最终累积平均。但是通过打印语句，我发现平均值设置为最后的（权重[i] *得分[i]）操作，忽略先前的平均值（或将其取为0）。例如，如果权重[] = {。3，.3，.4}和得分[] = {。4，.4，.4}。累积平均值应为.4，但我的程序告诉我.32，这是权重的最后一个值乘以最后一个得分值。

methods.c：

#include <stdio.h>
#include "methods.h"

int howManyCategories()
{
 int categories = 0;
 int firstTime = 0;

 while(1)
 {
  if(firstTime == 0)
  {
   fprintf(stdout, "\nHow many categories are you currently graded on? ");
   scanf("%d", &categories);
  }
  else
  {
   fprintf(stdout, "\nThat's not a valid value, try a positive integer. ");
   scanf("%d", &categories);
  }

  firstTime++;

  if(categories > 0)
  {
   return categories;
  }
 }
}

double howMuchWeight(int categories)
{
 double weight = 0;

 while(1)
 {
  if(categories == 1)
  {
   fprintf(stdout, 
   "\nThis %d category accounts for how much of your grade? (.1, .85, 1 etc.) ", 
   categories);
   scanf("%lf", &weight);
  }
  else
  {
   fprintf(stdout, 
   "\nThese %d categories account for how much of your grade? (.1, .85, 1 etc.) ", 
   categories);
   scanf("%lf", &weight);
  }

  if(weight > 1 || weight <= 0)
  {
   fprintf(stdout, 
   "\nRemember, total weighting must be positive and no larger than 1" 
   " (100 percent). \nTry Again.\n");
  }
  else 
  {
   return weight;
  }
 }
}

double findWeightsAndScores(int i, double categories, 
                            double checkWeights, double totalWeight, 
                            double scores[])
{
 while(1)
 {
  double piece = 0;
  int count = i + 1;

  fprintf(stdout, "\nWeight for category %d: ", count);
  scanf("%lf",&piece);

  if(piece > 0 && piece < 1)
  {
   findScores(i, &scores[i]);
   return piece;
  }
  else
  {
   fprintf(stdout, "\nRemember, weights must be positive and less than 1!\n");
  }
 }
}

void findScores(int i, double scores[])
{
 int validScore = 0;

 while(validScore == 0)
 {
  int count = i + 1;
  double score = 0;

  fprintf(stdout, "Please enter your percentage score in category %d: ", count);
  scanf("%lf", &score);

  if(score >= 0 && score <= 1)
  {
   scores[i] = score;
   validScore = 1;
  }
  else
  {
   fprintf(stdout, "\nRemember, scores in each category must be positive, no greater "
   "than 1 (100 percent) and no less than 0, try again.\n\n");
  }
 } 
}

double findAverage(int categories, double weights[], double scores[])
{
 double average = 0;

 for(int i = 0; i <= categories - 1; i++)
 {
  average += (weights[i] * scores[i]);
  fprintf(stdout, "%lf", average);
 }

 return average;
}

methods.h：

#ifndef METHODS_H_
#define METHODS_H_

int howManyCategories();
double howMuchWeight(int categories);
double findWeightsAndScores(int i, double categories, 
       double checkWeights, double totalWeight, double scores[]);
void findScores(int i, double scores[]);
double findAverage(int categories, double weights[], double scores[]);

#endif

whatsmyGrade.c：

#include <stdio.h>
#include "methods.h"

int main()
{
 while(1)
 {
  /*Prompts for categories*/
  int categories = howManyCategories();
  int dataProvided = 1;

  double checkWeights = 0;
  double grade = 0;
  double average = 0;

  /*Prompts for total weight*/
  double totalWeight = howMuchWeight(categories);

  double category[categories];
  double weights[categories];
  double scores[categories];

  /*Assign weights to each category and score in each category*/ 
  for(int i = 0; i <= categories - 1; i++)
  {        
   /*Fill array for weights*/ 
   weights[i] = findWeightsAndScores(i, categories, checkWeights, totalWeight,
   scores);

   checkWeights = checkWeights + weights[i];

   if(checkWeights != totalWeight && i == categories - 1)
   {
    fprintf(stdout, "\nYour weight distribution is invalid! Try again.\n");
    dataProvided = 0;
    break;
   }
  } 

  /*Calculate total grade*/
  if(dataProvided == 1)
  {
   average = findAverage(categories, weights, scores);

   grade = (average / totalWeight) * 100;
   fprintf(stdout, "Your cumulative average is %.2lf percent\n\n", grade);

   return 1;
  }


 }/*End of parent while loop*/ 
}/*End of main*/

提前谢谢

Answer 1

你的问题出在其他地方，因为它对我来说就像一个魅力：

#include <stdio.h>

double findAverage(int categories, double weights[], double scores[])
{
    double average = 0;
    int i;
    for(i = 0; i <= categories - 1; i++) {
        average += (weights[i] * scores[i]);
        fprintf(stdout, "%lf  ", average);
    }

    return average;
}

int main(void) {
    // your code goes here
    double average;
    double grade;
    int categories = 3;
    double totalWeight = .3 + .3 + .4;
    double weights[] = {.3, .3, .4};
    double scores[] = {.4, .4, .4};

    average = findAverage(categories, weights, scores);

    grade = (average / totalWeight) * 100;
    fprintf(stdout, "\nYour cumulative average is %.2lf percent\n\n", grade);

    return 0;
}

Answer 2

知道了，当我在findWeightsAndScores函数中调用findScores函数时，我正在传递它＆amp;得分[i]当我应该通过它得分时。谢谢你们

for / while循环不能正确更新值

2 个答案: