c++ - 如何通过函数 C++ 链接数组值

Question

我终于解决了并通过 strcmp 链接数组以发挥作用并比较数组值。感谢你的帮助!!希望你们能引用我的问题和帖子中列出的答案。

感谢所有发表评论并提出相应建议的人。欣赏它。

我的解决方案是通过使用 2D 数组 - char 而不是字符串 + 使用 strcmp at 函数来比较值集以实现 Lab7 的目标来解决它。

最好的，

MM

// Marcus Moo Lab 7.cpp
// Full Time Student
// No plagarism

#include <iostream>
#include <string>
using namespace std;

// Global Declarations
const float pointLaw[11] = { 5.0,5.0,4.5,4.0,3.5,3.0,2.5,2.0,1.5,1.0,0.0 };
const char gradeLaw[11][3] = { "A+","A","A-","B+","B","B-","C+","C","D+","D","F" };

// Convert Grade to Point
float gradeToPoint(const char grade[]);

int main()
{
    // Header
    cout << "\tWelcome to University Of Wollongong" << endl;
    cout << "Grade Point Consultation System" << endl;
    cout << endl;

    // Defining moments
    char grade[3];
    float outcome;
    char intent;
    int count;

    // Purpose of consultation system
    do
    {
        cout << "Enter your grade: ";
        cin >> grade;
        outcome = gradeToPoint(grade);
        if (outcome == -1) {
            cout << "Invalid Grade" << endl;
        }
        else {
            cout << "Your grade point is " << outcome << endl;
        }
        cout << "Continue?: ";
        cin >> intent;
        cout << endl;

    } while ((intent == 'y') || (intent == 'Y'));

    // The end
    cout << "All the best" << endl;
}

float gradeToPoint(const char grade[])
{
    int count;
    float points = -1;
    for (count = 0; count < 12; count++)
    {
        if (strcmp(gradeLaw[count], grade) == 0) {
            points = pointLaw[count];
            cout << gradeLaw[count] << " = " << grade << endl;
        }
    }
    return points;
}

Answer 1

更简单的方法是使用结构对记录建模(想想表中的一行):

struct Name_Grade
{
  std::string grade;
  double      point;
};

这会将成绩与分值配对。

现在声明每个数组:

static const grade_table[] =
{
  {"A+", 5.0}, {"A", 5.0}, {"A-", 4.5}, //...
};
size_t rows_in_table =
  sizeof(grade_table) / sizeof(grade_table[0]);

你的函数变成:

double gradeToPoint(const std::string& grade)
{
  double point = 0.0;
  for (size_t i = 0; i < rows_in_table; ++i)
  {
    if (grade == grade_table[i].grade)
    {
      point = grade_table[i].point;
      break;
    }
  }
  return point;
}

使用并行数组:

double grade_to_point(const std::string& grade)
{
  static const std::string grade_texts[]=
     {"A+", "A", "A-",
      "B+", "B", "B-",
      "C+", "C", "C-",
      "D+", "D",
      "F"};
  static const double point[] = 
     {5.0,5.0,4.5,
      3.5,3.0,2.5,
      2.5,2.0,1.5,
      1.0,0.5,
      0.0};
  static const size_t grade_quantity =
      sizeof(point) / sizeof(point[0]);

  double grade_value = 0.0;
  for (size_t i = 0; i < grade_quantity; ++i)
  {
    if (grade == grade_texts[i])
    {
      grade_value = point[i];
      break;
    }
  }
  return grade_value;
}

并行数组的一个问题是数组的大小可能不同，或者不同步。因此，更安全、更可靠的方法是将成绩文本与分值保持一致(struct 方法)。