2012-11-02 121 views
1

我正在嘗試對二維結構數組(即每個結構包含一個結構數組的結構數組)進行排序。我的代碼正確地排序父結構和父結構。但是,當父結構被交換到正確的位置時,它內部的結構數組被重置爲其原始順序。排序二維結構數組

注意:學生姓名必須包含名和姓(或程序將崩潰)。此外,等級必須是大寫字母「A」,「B」,「C」,「D」或「F」。我必須使用我編寫的排序算法(我選擇了冒泡排序)。我不能使用向量或排序()函數等。(這是家庭作業)

Current Output: 

Enter student name: Bob Chatter 
Enter class title: Chem 
Enter units for Chem: 3 
Enter grade for Chem: A 
Enter class title: Bio 
Enter units for Bio: 3 
Enter grade for Bio: B 
Enter class title: Algebra 
Enter units for Algebra: 4 
Enter grade for Algebra: A 
Enter class title: 
Enter student name: Frank Brandon 
Enter class title: Music 
Enter units for Music: 3 
Enter grade for Music: A 
Enter class title: 
Enter student name: Brad Anderson 
Enter class title: CoSci 
Enter units for CoSci: 3 
Enter grade for CoSci: A 
Enter class title: 
Enter student name: 
Student's name: Bob Chatter 
Chem,A 
Bio,B 
Algebra,A 
GPA: 3.70 
Student's name: Frank Brandon 
Music,A 
GPA: 4.00 
Student's name: Brad Anderson 
CoSci,A 
GPA: 4.00 
Student's name: Brad Anderson 
CoSci,A 
GPA: 4.00 
Student's name: Frank Brandon 
Music,A 
GPA: 4.00 
Student's name: Bob Chatter 
Chem,A 
Bio,B 
Algebra,A 
GPA: 3.70 
Press any key to continue . . . 

鮑勃聊友類進行排序,當我調試他們正確排序,直到學生們按姓氏排序,在這指出類重置的排序。

#include <iostream> 
#include <string> 
#include <stdio.h> 
#include <string.h> 
#include <iomanip> 
using namespace std; 


struct Class 
{ 
    string title; 
    int units; 
    char grade; 

}; 
struct Student 
{ 
    string name; 
    double gpa; 
    Class classes[500]; 
}; 

int const SIZE = 50; 
void initStudent(Student[], int); 
void readStudent(Student[], int, int&); 
void gpaCalculate(Student&); 
void print(Student[], int); 
void stringToCharArray (string, char[]); 
string returnLastName(string); 
void sort_name(Student[], int); 
void bubbleUpLastName(Student[],int, int); 
void bubbleUpClass(Student[],int, int); 
void swapStu(Student&, Student&); 
void swapStusClass(Class&, Class&); 


int main() 
{ 
    int numberOfStudents = 0; 
    Student students[SIZE]; 
    initStudent(students, SIZE); 
    readStudent(students, SIZE, numberOfStudents); 

    for(int i = 0; students[i].name != "";i++) 
     gpaCalculate(students[i]); 
    print(students, numberOfStudents); 
    sort_name(students, numberOfStudents); 
    print(students, numberOfStudents); 
    system("pause"); 
    return 0; 
} 
void initStudent(Student st[], int s) 
{ 
    for(int i = 0; i < s; i++) 
    { 
     st[i].gpa = 0.0; 
    } 

} 

void readStudent(Student st[], int s, int& nStus) 
{ 
    for(int i = 0; i < s; i++) 
    { 
     string tmpName; 

     cout << "Enter student name: "; 
     getline(cin, tmpName); 
     if(tmpName == "") 
      break; 
     st[i].name = tmpName; 
     nStus++; 


     for(int j = 0; j < 500; j++) 
     { 
      string tmpTitle; 
      cout << "Enter class title: "; 
      getline(cin, tmpTitle); 
      if (tmpTitle == "") 
       break; 
      st[i].classes[j].title = tmpTitle; 

      cout << "Enter units for " << st[i].classes[j].title << ": " ; 
      cin >> st[i].classes[j].units; 
      cout << "Enter grade for " << st[i].classes[j].title << ": " ; 
      cin >> st[i].classes[j].grade; 
      cin.ignore(); 
     } 
    } 
} 


void gpaCalculate (Student& s) 
{ 
    double unitsByPoints = 0; 
    double totalUnits = 0; 

    for (int i = 0; s.classes[i].title != ""; i++) 
    { 

     int grade = 0; 
     char ltrGrade = s.classes[i].grade; 
     switch (ltrGrade) 
     { 
     case 'A': 
      grade = 4; 
       break; 
     case 'B': 
      grade = 3; 
       break; 
     case 'C': 
      grade = 2; 
       break; 
     case 'D': 
      grade = 1; 
       break; 
     case 'F': 
      grade = 0; 
       break; 
     } 
     unitsByPoints += s.classes[i].units*grade; 
     totalUnits += s.classes[i].units; 

    } 
    s.gpa = unitsByPoints/totalUnits; 
} 

void print(Student st[], int size) 
{ 

    for (int i = 0; i < size; i++) 
    { 
     cout << "Student's name: " << st[i].name << endl; 
     for (int j = 0; st[i].classes[j].title != ""; j++) 
     { 
      cout << st[i].classes[j].title << "," << st[i].classes[j].grade << endl; 
     } 
     cout << fixed << setprecision(2) << "GPA: " << st[i].gpa << endl; 
    } 
} 

// Returns the last name of the student passed in 
string returnLastName(string s) 
{ 
    int i = 0; 
    while (s[i] != ' ') 
    { 
     i++; 
    } 
    return s.substr(i + 1, s.length() - (i + 1)); 
} 

//sorts the students according to name and their classes according to their title 
void sort_name(Student st[], int numValues) 
{ 
    int stuCurrent = 0; 
    int numClasses = 0; 
    while (stuCurrent < numValues - 1) 
    { 
     int classCurrent = 0; 
     for(int i = 0; st[stuCurrent].classes[i].title != ""; i++) 
     { 
      numClasses = i; 
     } 
     while (classCurrent < numClasses) 
     { 
      bubbleUpClass(st,classCurrent,stuCurrent); 
      classCurrent++; 
     } 


     bubbleUpLastName(st, stuCurrent, numValues-1); 

      stuCurrent++; 
    } 
} 

// Moves the student with the last name that should be first alphabeticaly into the first position of the Student array 
void bubbleUpLastName(Student st[],int startIndex, int numValues) 
{ 
    for (int index = numValues; index > startIndex; index--) 
    { 
     if ((returnLastName(st[index-1].name).compare(returnLastName(st[index].name)) > 0)) 
     { 
      swapStu(st[index], st[index-1]); 
     } 
    } 
} 

// Moves the Class that should be first alphabeticaly (according to title) into the first position of the Class array 
void bubbleUpClass (Student st[],int startIndex, int stuIndex) 
{ 
    int numValues = 0; 
    for(int i = 0; st[stuIndex].classes[i].title != ""; i++) 
     numValues = i; 
    for(int index = numValues; index > startIndex; index--) 
    { 
     if(st[stuIndex].classes[index - 1].title.compare(st[stuIndex].classes[index].title)) 
     { 
      swapStusClass(st[stuIndex].classes[index], (st[stuIndex].classes[index - 1])); 
     } 
    } 
} 
void swapStu(Student& s1, Student& s2) 
{ 
    Student tmp; 
    tmp = s1; 
    s1 = s2; 
    s2 = tmp; 
} 

void swapStusClass(Class& c1, Class& c2) 
{ 
    Class tmp; 
    tmp = c1; 
    c1 = c2; 
    c2 = tmp; 
} 

/* 



Define a structure called Class (with uppercase C) with the following data: 
title, units and grade. 

Define a structure called Student with the following data: 
name (full name), gpa, and classes which is an array of Class structures (all the classes the student has taken so far). 

Write an initialize function that receives an array of Student structures and its size and sets the gpa of all to 0.0. 

In main, create 50 Students and call the above function to initialize the gpa for all 50 Students to 0.0. 

Then, pass the array of student structures and its size to a read function that will read student data from the user and store the entered data in the array of student structures. The user will enter student name followed by the class title, units and grade received for each class he or she has taken. When finished entering class information for a student, the user will just press Enter (an empty string) and to end entering more students, he or she will do the same for the student name. 

Example: 

Enter student name: Maria Gomez 

Enter class title: English 101 
Enter units for English 101: 3 
Enter grade for English 101: A 

Enter class title: Math 201 
Enter units for Math 201: 4 
Enter grade for Math 201: B 

Enter class title: [User enters RETURN to indicate no more classes] 

Enter student name: Kevin Duran 

Enter class title: Poly Sci 101 
Enter units for Poly Sci 101: 3 
Enter grade for Poly Sci 101: A 

Enter class title: Math 201 
Enter units for Math 201: 4 
Enter grade for Math 201: B 

Enter class title: [User enters RETURN to indicate no more classes] 

Enter student name: [User enters RETURN to indicate no more students] 

Once all Studnets have been entered, pass each element of the array of Student structures (element by element) to a gpa function which will compute and return the gpa for each Student using the classes array within each Student structure which contains the units and grade for each class taken by the student. Store the gpa returned by the above function in the gpa member of the Student structures. GPA is calculated by multiplying the number of units for each class by the points received for that class, and then adding all these products together and dividing it by total number of units. The points received for a class is based on the grade: for A, it's 4; for B, it's 3; for C, it's 2; for D it's 1; and for F it's 0. For example, if a student has take 3 classes with 3, 4, and 3 units and has received A, B, and C for these classes, respectively, then, the GPA will be 3 x 4 + 4 x 3 + 3 x 2/10 = 3.0. 

Print all students showing name, followed by all classes taken, the grade received and the gpa using a display function which receives the array and its size as parameters. 

Then, using a sort_name function, sort the student structures based on their last names and for each student, sort the classes he or she is taking based on class title. Display the sorted list of students using the display function by calling it from main. 

For example: 

Kevn Duran 
Poly Sci 101, A 
Math 150, B 
GPA: 3.0 

Maria Gomez: 
English 101, A 
Math 201, C 
GPA: 2.9 

Robert Small 
Comp Science 801, C 
Comp Science 802, D 
GPA: 1.9 

Tom Wang 
Comp Science 808, A 
Comp Science 839, B 
GPA: 3.5 

Then, sort the students based on their GPA's using a sort_gpa function and print the list again using the display function. 

Then, ask what to search for - name or gpa. If name is selected, read a student name from the user and, using a binary search function that takes the array, its size and the name to search for, finds the student and displays all of his or her information (name, gpa, units and list of classes taken). 

Example: 

Enter a student name: Robert Small 

Robert Small: 
Comp Science 801, C 
Comp Science 802, B 
GPA: 2.5 

If GPA is selected, read a GPA and using another binary search find the student with the given GPA by passing the students array, its size and the GPA to search for. Display the name of the student with the specified GPA in main. 

Example: 

Enter GPA to search for: 2.5 

Robert Small was found with the GPA of 2.5 

If the name or GPA is not found, tell the user it was not found; e.g.: There was no student with a GPA of 2.5; or Robert Small was not found. 

Then, pass the array of student atructures and the size to a stats function which will return the average of the GPA's of all students and through two reference parameters will output the student structures that have the minimum and maximum GPA's. Print the average GPA, as well as the names of the students who have the minimum and maximum GPA in main, like so: 

Average GPA = 3.17 

Robert Small has the minimum GPA of 2.5. 

Tom Wang has the maximum GPA of 3.5. 

Finally, read a maximum and minimum GPA from the user and pass the array of student structures and its size, as well as two other arrays of student structures of the same size to a function which will store all students with a GPA of above the minimum in the highGPA array and all those with a GPA below the maximum in the lowGPA array. Display the students stored in these two arrays by passing them each from main to the display function. In other words, the highlow function receives two uninitalized arrays of student structures and populates them based on the GPA criteria passed to it (minimum GPA and maximum GPA). Then, upon return to main, main passes each of these arrays to the display function to display them. For example, if the user enters 2.0 for the maximum GPA, the lowGPA array gets filled out with all those students who have a GPA of less than 2.0. Likewise, if the minimum GPA is 3.5, the highlow function populates the highGPA array with those students who have a GPA of 3.5 or higher. 

Example: 

Enter maximum GPA: 2.0 

Enter minimum GPA: 3.5 

Students with a GPA of lower than 2.0: 

Robert Small 1.9 

Students with a GPA of 3.5 or higher: 

Tom Wang 3.5 

When writing the highlow function, take advantage of the fact that the array elements are sorted based on the GPA, so to find all the students with a GPA of equal to or higher than the minimum GPA, it doesn't make sense to start from the first element in the array. Instead you can start from the midpoint. If the midpoint is lower than the minimum GPA, you can increment the index until the midpoint is no longer smaller and then all the GPA's from that point on will be larger and part of the high GPA's. For low GPA's of course, you'd want to start from the beginning of the array and compare and store each that's lower than the maximum until they are no longer lower. 

Functions you must write for this assignment (in addition to main): 

initialize, read, display, sort_name, sort_gpa, search-name, search_gpa, stats, highlow. 

Upload your cpp and exe files using the Browse and Upload buttons below and click Finish once both have been uploaded to the site.*/ 

什麼是導致父結構中的結構數組被重置?

+1

你有問題嗎? –

+0

什麼是導致父結構中的結構數組被重置。 – Zzz

+0

顯示您認爲產生錯誤輸出的最簡單的輸入。同時顯示輸出和此示例的預期輸出。 – PiotrNycz

回答

1

當比較Class::title你忘了添加比較來比較值:

你行:

if(st[stuIndex].classes[index - 1].title.compare(st[stuIndex].classes[index].title)) 

應該是:

if(0 < st[stuIndex].classes[index - 1].title.compare(st[stuIndex].classes[index].title)) 

我說你忘了 - 因爲你有這個明確的在你的功能比較排序學生。

現在解釋你的結果:首先,偶然 - 對某些學生的課程進行排序,但在此之後,學生的位置發生變化(這是冒泡排序),然後對這些課程進行下一個排序 - 因此,實際上,您不會對課程進行排序,而只是更改其位置,您可以在下一步中獲得其原始序列。


作爲獎勵,我建議不要使用比較排序 - 只需使用operator <

if(st[stuIndex].classes[index - 1].title < st[stuIndex].classes[index].title) 

簡單多了,是不是?

+0

感謝您的幫助,我一直在尋找更復雜的東西。此外,我的一個陳述是關閉:) – Zzz