Question

我在将文本输入char数组时遇到了一些麻烦。当我为数组设置静态大小时，它工作正常，如

char speech[15000];

但效率低下，所以我尝试使用calloc。这使它停止工作。数组的大小合适，但没有任何内容写入。这是相关的代码。我做错了什么？

int main() {

FILE* inFile;
int i;
int count = 0;

printf("\nOpening file April_30_1789.txt\n");

inFile = fopen("./speeches/April_30_1789.txt", "r");

if(inFile == NULL) {
    printf("Could not find April_30_1789.txt\n");
    return -1;
}

char ch;

while((ch = fgetc(inFile) != EOF)) count++;

rewind(inFile);

int size = count;

printf("Size of the array is %d\n", size);

char *speech = (char *)malloc(size*sizeof(char) + 1*sizeof(char));

fscanf(inFile, "%s", speech);

printf("Closing the file.\n");
fclose(inFile);

printf("%s", speech);

printf("\n\nDone\n");

return 0;

}

目前，这给了我

Opening file April_30_1789.txt
Size of the array is 8617
Closing the file.
Fellow-Citizens

Done

Answer 1

Reading the whole text file into a char array in C可能重复。

带有fscanf格式的

您的问题："%s"会读到遇到的第一个空格。

可能的解决方案（为简明起见，省略了错误检查）：

#include <stdio.h>  /* printf */
#include <stdlib.h> /* fopen, fseek, ... */

char *buffer = NULL;
size_t size = 0;

/* Open your_file in read-only mode */
FILE *fp = fopen("your_file_name", "r");

/* Get the buffer size */
fseek(fp, 0, SEEK_END); /* Go to end of file */
size = ftell(fp); /* How many bytes did we pass ? */

/* Set position of stream to the beginning */
rewind(fp);

/* Allocate the buffer (no need to initialize it with calloc) */
buffer = malloc((size + 1) * sizeof(*buffer)); /* size + 1 byte for the \0 */

/* Read the file into the buffer */
fread(buffer, size, 1, fp); /* Read 1 chunk of size bytes from fp into buffer */

/* NULL-terminate the buffer */
buffer[size] = '\0';

/* Print it ! */
printf("%s\n", buffer);

Answer 2

正如pmg所说，while((ch = fgetc(inFile) != EOF)) count++;使你的文件指针指向最后，使用rewind(FILE* fileptr);返回文件的开头。

Answer 3

您的文件指针inFile指向结束

我会做以下事情：

long lSize;

fseek( inFile , 0L , SEEK_END); //use the function instead
lSize = ftell( inFile );       // to know the file size
rewind( inFile );             // Now point to beginning 

char* speech = calloc( 1, lSize+1 );
if( speech )
{
    if( fread( speech , lSize, 1 , inFile) != 1)
    {
      fclose(inFile) ;
      free(speech); 
      exit(1);
    }
}

// Process the speech Here


fclose(inFile); 
free(speech); // Don't forget to free the allocated memory !

将文本文件读入char数组

3 个答案: