c - 如何使用 C 中的结构和选择排序按字符串对文件进行排序

Question

排序的打印不正确，排序可能是错误的。我也不确定如何计算每个字符串中的平均成绩。这是示例输出:

Original:
+-------------------------+--------------+------+------+---------+---------+-------+-----+
| Student Name|Identification|Exam 1|Exam 2|Project 1|Project 1|Average|Grade|
+-------------------------+--------------+------+------+---------+---------+-------+-----+
| Holtkamp, Norman| N21102485| 83| 61| 62| 78| 71.00| C|
| Bellomy, Shavonda| N94185259| 74| 96| 80| 98| 87.00| B|
| Clutter, Loris| N68760306| 83| 68| 93| 70| 78.50| C|
| Rountree, Edythe| N76813896| 98| 91| 90| 81| 90.00| A|
| Waldeck, Marylee| N44293872| 88| 100| 70| 87| 86.25| B|
+-------------------------+--------------+------+------+---------+---------+-------+-----+
Sorted:
+-----+-------------------------+--------------+------+------+---------+---------+-------+-----+
|Index|             Student Name|Identification|Exam 1|Exam 2|Project 1|Project 1|Average|Grade|
+-----+-------------------------+--------------+------+------+---------+---------+-------+-----+
| 1   |         Rountree, Edythe|     N76813896|    98|    91|       90|       81|  90.00|    A|
| 2   |        Bellomy, Shavonda|     N94185259|    74|    96|       80|       98|  87.00|    B|
| 3   |         Waldeck, Marylee|     N44293872|    88|   100|       70|       87|  86.25|    B|
| 4   |           Clutter, Loris|     N68760306|    83|    68|       93|       70|  78.50|    C|
| 5   |         Holtkamp, Norman|     N21102485|    83|    61|       62|       78|  71.00|    C|
+-----+-------------------------+--------------+------+------+---------+---------+-------+-----+

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
//Struct groups each line in the file
struct gradesRecord
    {
        int iIndex; // index on the file
        char cStudentName[26]; // student name field
        char iStudentINDnum[9];  // 'Student id ' field
        int iExamGrouped[2];  // 'Exam 1'..'Exam 2' fields
        int iProjectGrouped[2];
        float fAverage;
        char cStudentGD; // 'Grade' field
    };
void printUnsortedStringFromFile(int amount, struct gradesRecord A[]);
void printSortedStringFromFile(int amount, struct gradesRecord A[]);
void flushScanf();
int main()
{
    FILE* spData = fopen("records.ssv", "r");
    int ch, number_of_lines = 0;
    do
    {
        ch = fgetc(spData);
        if (ch == '\n')
            number_of_lines++;
    } while (ch != EOF);

    if (ch != '\n' && number_of_lines != 0)
        number_of_lines++;

    fclose(spData);
    printf("There are %d lines in file records.ssv . \n", number_of_lines);
    int amount = number_of_lines;
    struct gradesRecord A[amount];
    printUnsortedStringFromFile(amount, A );
    printSortedStringFromFile(amount, A );
    //flushScanf();
    return 0;
}

/*
* Function Name: printUnsortedStringFromFile
*
* Input Parameters: takes array A
*
* Description: This fuction prints the original list that was unsorted in grades.csv
*
* Return Value: void
*/
void printUnsortedStringFromFile(int amount, struct gradesRecord A[amount])
{
    FILE *spData;
    spData = fopen("records.ssv", "r");
    if(spData == NULL)
    {
        fprintf(stderr, "Error opening the file records.ssv.\n");
        exit(1);
    }
    printf("+---------------------+--------------+------+------+---------+---------+-----+\n");
    printf("|         Student Name|Identification|Exam 1|Exam 2|Project 1|Project 2|Grade|\n");
    printf("+---------------------+--------------+------+------+---------+---------+-----+\n");
    char sLine[amount]; //local string to read one row
    int j = 0; //storage index
    while((fgets(sLine, amount, spData)) != NULL)
    {
    sscanf(sLine, "%20[^;] ; %9[^;] ; %5d ; %5d ; %5d ; %5d ; %c",
        A[j].cStudentName, A[j].iStudentINDnum, &(A[j].iExamGrouped[0]), &(A[j].iExamGrouped[1]),
        &(A[j].iProjectGrouped[0]), &(A[j].iProjectGrouped[1]), &(A[j].cStudentGD));
    if(strcmp(A[j].cStudentName, " ")> 0){
    printf("| %20s|     %9s| %5d| %5d|   %5d|     %5d|    %c| \n",
        A[j].cStudentName, A[j].iStudentINDnum, A[j].iExamGrouped[0], A[j].iExamGrouped[1],
        A[j].iProjectGrouped[0], A[j].iProjectGrouped[1], A[j].cStudentGD);
    }
    j++; // next row
    }
    printf("+---------------------+--------------+------+------+---------+---------+-----+\n");

    if (fclose(spData) == EOF)
    {
        fprintf(stderr, "Error closing the file records.ssv. \n");
        exit(2);
    }
}

/*
* Function Name: printSortedStringFromFile
*
* Input Parameters: takes int amount, struct gradesRecord A
*
* Description: This function prints the sorted version of the file grades.csv omitting
*               the exam values and giving each string a index number
*
* Return Value: void
*/

void printSortedStringFromFile(int amount, struct gradesRecord A[amount])
{
    FILE *spData;
    spData = fopen("records.ssv", "r");
    if(spData == NULL)
    {
        fprintf(stderr, "Error opening the file grades.csv.\n");
        exit(1);
    }

    char sLine[amount];
    int iLine = 0, iRow;
    int x;
    struct gradesRecord grRow;

    while((fgets(sLine, amount, spData)) != NULL)
    {
    // extract one Row and store it into grRow
    sscanf(sLine, "%20[^;] ; %9[^;] ; %5d ; %5d ; %5d ; %5d ; %2.2f ; %c",
        grRow.cStudentName, grRow.iStudentINDnum, &(grRow.iExamGrouped[0]), &(grRow.iExamGrouped[1]),
        &(grRow.iProjectGrouped[0]), &(grRow.iProjectGrouped[1]), &(grRow.fAverage), &(grRow.cStudentGD));
    // keep the line index of that row
        grRow.iIndex = iLine;
    // target loop = Selection sort algorithm
    for (iRow = 0; iRow < iLine - 1; iRow++){
        for(x = iRow + 1; x < iLine; x++){
        if (A[iRow].cStudentGD < A[x].cStudentGD) {
            struct gradesRecord tmp = A[iRow];
            A[iRow] = A[x];
            A[x] = tmp;
        }
        }
    }
        int j = 0;
    printf("+-----+---------------------+--------------+------+------+---------+---------+-------+-----+\n");
    printf("|Index|         Student Name|Identification|Exam 1|Exam 2|Project 1|Project 2|Average|Grade|\n");
    printf("+-----+---------------------+--------------+------+------+---------+---------+-------+-----+\n");

        int index;
        while (j < amount - 1)
    {
        index = j+1;
        printf("| %4d| %20s|     %9s| %5d| %5d| %5d| %5d| %2.2f|  %c| \n",
        index, A[j].cStudentName, A[j].iStudentINDnum, A[j].iExamGrouped[0], A[j].iExamGrouped[1],
        A[j].iProjectGrouped[0], A[j].iProjectGrouped[1], A[j].fAverage, A[j].cStudentGD);
        j++;
    }
    printf("+----+---------------------+--------------+------+------+---------+---------+-----+\n");
    if (fclose(spData) == EOF)
    {
        fprintf(stderr, "Error closing the file records.ssv. \n");
        exit(2);
    }
}
}

这里是“records.ssv”的信息

Panzer, Lelia;N58288536;89;82;91;65;BBasler, Jennifer;N42495906;74;71;87;91;BLeaton, Cindi;N66735910;67;93;76;79;CBishop, Carolyne;N85576519;86;94;92;69;BLucey, Callie;N55890919;86;84;88;87;BTweed, Mirta;N94974972;62;95;85;92;BFontenot, Rosette;N44585447;98;62;74;74;CHoltkamp, Norman;N21102485;83;61;62;78;CBellomy, Shavonda;N94185259;74;96;80;98;BClutter, Loris;N68760306;83;68;93;70;CRountree, Edythe;N76813896;98;91;90;81;AWaldeck, Marylee;N44293872;88;100;70;87;BPutnam, Tuyet;N82771281;69;99;68;67;CMichaels, Arnette;N33948917;86;65;99;64;CStrawder, Wendolyn;N05586646;86;64;80;97;BMontufar, Melvin;N36545740;80;61;74;92;CFey, Letha;N61908241;73;89;71;68;CDeluna, Vaughn;N74322300;94;69;67;60;CWever, Marguerita;N37176367;95;92;95;70;BBuckingham, Lena;N87562246;95;64;89;71;CFridley, Verona;N53223806;67;83;71;61;CEbarb, Gladis;N66138130;89;70;87;90;BTichenor, Monika;N40314334;88;62;62;100;CDoran, Novella;N24182986;78;62;65;71;DRelyea, Mazie;N64652923;89;95;72;76;BKendall, Roma;N22064372;91;84;72;88;BBrannock, Henriette;N19795353;67;92;63;90;CLaine, Clint;N83838870;88;83;82;77;BReichenbach, Sharleen;N02253867;81;96;91;73;BEvers, Hanna;N05833153;75;79;75;98;BRegina, Amal;N52372967;95;73;73;89;BLightle, Desmond;N81006603;75;66;61;71;DYeoman, In;N30566266;89;99;98;89;AGarling, Nereida;N05192538;89;92;74;99;BHanna, Assunta;N39624931;91;80;72;80;BDanko, Mignon;N47365488;79;67;86;65;CUrich, Virgen;N57019166;70;82;72;88;CCzapla, Ermelinda;N38233556;93;83;60;87;BHapp, Mina;N46726472;84;98;60;66;CSudderth, Deloris;N88538002;86;71;82;82;BPalermo, Kenna;N44857147;72;69;83;75;CWiedemann, Usha;N29831009;86;78;89;81;BSaeed, Ruth;N47933985;78;62;99;99;BBurell, Colin;N75299461;77;85;99;99;AHeckert, Edie;N58264115;92;96;96;89;APolley, Denver;N77063394;99;95;65;95;BWeaver, Blanch;N59717716;66;80;89;80;CKibble, Glinda;N68212959;94;95;66;94;BKirker, Willis;N17878125;71;60;87;79;CLivesay, Arie;N91011529;89;60;60;84;C

Answer 1

1. 在 printUnsortedStringFromFile() 和 printSortedStringFromFile() 中你有

   sscanf(sLine, "%20[^;]…
   

   要读入 cStudentName，但是 20 个字符对于 Reichenbach, Sharleen 来说不够。由于您定义了 char cStudentName[26];，因此 25 的最大字段宽度就足够了。

2. 在 printSortedStringFromFile() 中有

   sscanf(sLine, "… %2.2f ; …
   

   在grRow.fAverage中读取，但是在records.ssv中没有这个字段，而A[j].fAverage是从未初始化。

3. 您说的排序可能是错误的是对的。这是因为在排序之前没有设置iLine:

   iLine = amount-1;   // You know that your 'amount' is 1 too high, don't you?