(C) 尝试将 .txt 文件读入二维数组（失败，请注意！）

Question

我用过很多 PHP 和一些 C++，但我对 C 是全新的，你可以从我乱七八糟的代码中看出这一点。基本上，我希望将 .txt 文件（网格，在这种情况下为我和我的朋友制作游戏）的内容读入 2d 数组，处理文件的内容，并将处理后的内容输出到单独的.txt 文件。

void grab_input(char *infile, int *rows, int *cols, char *buffer);
void send_output(char *outfile, int rows, int cols, char buffer);
int process_input(char *buffer);

int main(int argc, char *argv[])
{
    int rows;
    int cols;
    int i;
    char **buffer;
    if (argc != 2)
    {
        printf("Usage: %s filename\n", argv[0]);
        exit(EXIT_FAILURE);
    }
    buffer = (char**)malloc((rows + 2) * sizeof(char *));
    for (i = 0; i < rows; i++)
        buffer[i] = (char *)malloc(cols*sizeof(char));
    grab_input(argv[1], &rows, &cols, &buffer);
    process_input(&buffer);
    send_output(argv[2], rows, cols, *buffer);
    printf("\n%s\n", argv[2]);
    printf("%d\n", cols);

    return 0;
}

void grab_input(char *infile, int *rows, int *cols, char *buffer)
{
    FILE *input;
    input = fopen(infile, "r");
    if (input != 0)
        printf("The file exists.\n");
    else
        printf("No file.\n");
    fscanf(input, "%d %d", rows, cols);
    printf("Unprocessed grid:");
    while (fgets(buffer, (*rows+2) * (*cols+2) * sizeof(char)+1, input) != NULL)  {

        printf("%s", buffer);
    }
    fclose(input);
    printf("\nRows: %d\nColumns: %d\n", *rows, *cols);
}

为此，我收到多个控制台错误和“调试错误...变量 cols 周围的堆栈已损坏。”我在各个站点上阅读了大量有关动态内存分配的内容，但我显然不太了解如何将其付诸实践并从文件中创建动态分配的 2D 数组。如果您能帮助我，将不胜感激。

Here's a picture of my console window.

And here's one of the contents of my input.txt file.

非常感谢您的帮助。

Answer 1

应用所有 cmets 并清理逻辑并执行适当的错误检查，结果如下。

以下干净编译。

以下内容未经测试。

#include <stdio.h>  // fgets(), fopen(), fclose(), 
                    // sscanf(), fprintf(), printf()
#include <stdlib.h> // exit(), EXIT_FAILURE
#include <string.h> // memset()

void grab_sizeInfo( FILE *input, size_t *pRow, size_t *pCols );
void grab_input( FILE* fp_in, size_t rows, size_t cols, char **buffer);
void send_output(char *outfile, size_t rows, size_t cols, char **buffer);
void process_input(size_t rows, size_t columns, char **buffer);

int main(int argc, char *argv[])
{
    size_t rows = 0;
    size_t cols = 0;
    char **buffer = NULL;

    if (argc != 3)
    {
        fprintf(stderr, "Usage: %s InputFilename OutputFilename\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    FILE *fp_in = NULL;
    if( NULL == (fp_in = fopen( argv[1], "r") ) )
    { // then fopen failed
        perror( "fopen for input file failed" );
        exit( EXIT_FAILURE );
    }

    // implied else, fopen successful

    grab_sizeInfo( fp_in, &rows, &cols );
    printf("\nRows: %lu\nColumns: %lu\n", rows, cols);

    rows+=2;  // adjust for actual size
    cols+=2;  // adjust for actual size
    cols+=1;  // +1 to allow for NUL terminator byte

    if( NULL == ( buffer = malloc(rows * sizeof(char *)) ) )
    { // then malloc failed
        perror( "malloc for array of pointers to rows failed");
        fclose( fp_in );
        exit( EXIT_FAILURE );
    }

    // implied else, malloc for array of pointers to rows successful

    // prep array of pointers, to make cleanup easy
    memset( buffer, '\0', rows * sizeof(char *) );

    for ( size_t i = 0; i < rows; i++ )
    {
        if( NULL == (buffer[i] = malloc(cols) ) ) 
        { // malloc failed
            perror( "malloc for row failed" );
            // cleanup
            for( size_t j=0; j < rows; j++ )
            {
                free( buffer[j] );
            }
            free( buffer );
            fclose( fp_in );
            exit( EXIT_FAILURE );
        }

        // implied else, malloc for array of char in row successful

    } // end for each row

    grab_input( fp_in, rows, cols, buffer);
    fclose( fp_in );

    process_input(rows, cols, buffer);
    send_output(argv[2], rows, cols, buffer);

    printf("\n%s\n", argv[2]);
    printf("%lu\n", cols);

    return 0;
} // end function: main


void grab_sizeInfo( FILE *fp, size_t *pRow, size_t *pCols )
{
    char firstLine[20] = {'\0'};

    if( fgets( firstLine, sizeof firstLine, fp ) )
    { // successful read
        if( 2 != sscanf( firstLine, "%lu %lu", pRow, pCols) )
        { // then sscanf failed
            perror( "sscanf for rows and columns failed" );
            fclose( fp );
            exit(EXIT_FAILURE);
        }
    }
} // end function: grab_sizeInfo


void grab_input(FILE *fp, size_t rows, size_t cols, char **buffer)
{
    size_t rowNum = 0;
    while ( rowNum < rows && fgets( buffer[rowNum], (int)cols, fp ) )
    {
        printf("%s", buffer[rowNum]);
        rowNum++;
    }

    if( rowNum != rows )
    { // then failed to read complete file
        fprintf( stderr, "number of rows read: %lu Not equal Number expected rows: %lu\n", rowNum, rows );
        for( size_t i=0; i<rows; i++ )
        {
            free( buffer[i] );
        }
        free( buffer );
        fclose( fp );
        exit( EXIT_FAILURE );
    }
} // end function: grab_input