我的功能因某些奇怪的原因无法正常工作，不知道为什么

Question

我正在做这个大学项目。基本上我要做的就是使用文本文件。函数emptyLineCounter() 应该计算文件中的空行数。当在 v() 中调用时，它会执行预期的操作，稍后，我在 n() 中调用该函数。这是它失败并返回分段错误的地方。

#include <stdio.h>
#include <stdlib.h>

#define MAXSIZE 100

void checkArrayStatus() {
    //check if dynamic arrays (dynamicke polia) are created
}

int checkFileStatus(FILE *file, const char *filename) {
    //checks if file is open or close
    if (file != NULL) {
        return 1;
    } else {
        printf("Neotvoreny subor %s\n", filename);
        return -1;
    }
}

int emptyLineCounter(FILE *file) {
    //empty lines counter; number of empty lines == number of meassurments done
    int emptyLineCount = 1; //maybe rework this, doesn't count last line
    char line[MAXSIZE];

    while (fgets(line, sizeof(line), file) != NULL) {
        int isEmpty = 1; //assume line empty
        for (int i = 0; line[i] != '\0'; i++) {
            if (line[i] != ' ' && line[i] != '\t' && line[i] != '\n' && line[i] != '\r') {
                isEmpty = 0; // Line is not empty
                break;
            }
        }

        if (isEmpty) {
            emptyLineCount++;
        }

    }

    return emptyLineCount;
}

FILE* v() {
    //declare files as empty values
    FILE *dataloger = NULL;

    char *output[] = {"ID. mer. modulu:", "Pozícia modulu:", "Typ mer. veliciny:", "Hodnota:", "Cas merania:", "Datum merania:", ""};

    //if files not opened try to open them
    while (checkFileStatus(dataloger, "dataloger.txt") == -1) {
        dataloger = fopen("dataloger.txt", "r");
    }  

    if (1) { //change condition to false if n not pressed, use pointers probably
        char line[MAXSIZE];
        int pos = 0;
        while (fgets(line, sizeof(line), dataloger) != NULL) {
            if (pos == 7) {
                pos = 0;
            }
            printf("%s ", output[pos]);
            printf("%s", line);
            pos++;

        }
    }

    int measurement = emptyLineCounter(dataloger);

    return dataloger;
}

int n(FILE **file) {
    rewind(*file);
    if (checkFileStatus(*file, "dataloger.txt") == -1) {
        printf("Checking ... Failing\n");
        return -1;
    }
    printf("passed\n");

    printf("HERE: %d", emptyLineCounter(*file));//length of array based on number of measurmenets

    /*
    int dim1 = 3;
    int dim2 = 6; // Number of "inner" arrays
    char ***dynamicArray = (char ***)malloc(dim1 * sizeof(char **));

    //rework so that it accepts each line instead of input
    for (int i = 0; i < dim1; i++) {
        dynamicArray[i] = (char **)malloc(dim2 * sizeof(char *));
        for (int j = 0; j < dim2; j++) {
            dynamicArray[i][j] = (char *)malloc(256 * sizeof(char)); // Assuming a maximum string length of 255 characters
            printf("Enter a string for element [%d][%d]: ", i, j);
            scanf("%s", dynamicArray[i][j]);
        }
    }*/
    return 0;
}

void c() {
    printf("c\n");
}

void s() {
    printf("s\n");
}

void h() {
    printf("h\n");
}

void z() {
    printf("z\n");
}

int main() {
    //char to store user option
    char opt;

    FILE *v_val = NULL;
        
    //while true keep running -> end at option k
    while(1) {

        scanf("%s", &opt);

        switch(opt){
            //two cases to include capital/lowercase letters
            case 'v':
            case 'V':
                v_val = v();
                //printf("%p", v_val);
                break;
            case 'n':
            case 'N':
                n(&v_val);
                break;
            case 'c':
            case 'C':
                c();
                break;
            case 's':
            case 'S':
                s();
                break;
            case 'h':
            case 'H':
                h();
                break;
            case 'z':
            case 'Z':
                z();
                break;
            case 'k':
            case 'K':
                printf("end\n");
                //fclose(v_val);
                return 0;
            default:
                printf("Nesprávna možnosť\n"); //check for what the output should be
                break;
            printf("\n");
        }
    }

    return 0;
}

我不明白为什么该功能突然不起作用。我怀疑它连接到了我在 v <-> main <-> n 之间传递它们时使用的指针，但没有发现任何错误。

Answer 1

我尝试了你的代码。正如好的评论中所指出的，问题似乎很简单，就像尝试在“scanf”函数中读取一个字符，但表示一个字符数组（字符串）。

scanf("%s", &opt);

在测试您的代码时（仅供参考，我将字面措辞重构为英语）我能够复制分段错误。

craig@Vera:~/C_Programs/Console/Empty/bin/Release$ ./Empty 
Enter option: v
Unopened file dataloger.txt
ID. Measurement module: Module #1
Module position: 1
Type of measure quantities: Kilograms
Value: 80
Time of measurement: 10:00:00
Date of measurement: 25-Oct-2023
 
The empty line count when opening the file is: 1
Enter option: n
Segmentation fault (core dumped)

将 scanf 函数更改为以下语句似乎可以解决该问题。

scanf(" %c", &opt);

注意“%c”之前的空格。

这是代码的重新测试。

craig@Vera:~/C_Programs/Console/Empty/bin/Release$ ./Empty 
Enter option: v
Unopened file dataloger.txt
ID. Measurement module: Module #1
Module position: 1
Type of measure quantities: Kilograms
Value: 80
Time of measurement: 10:00:00
Date of measurement: 25-Oct-2023
 
The empty line count when opening the file is: 1
Enter option: n
passed
HERE: 1
Enter option: n
passed
HERE: 1
Enter option: k
end

因此，在使用“scanf”函数时，请始终了解用作接收器变量的数据类型。