Question

你好我想基于文本文件动态初始化一个数组，但由于某种原因，我做错了。我在第34行＆＃34; malloc＆＃34;那个＆＃34; texto＆＃34;没有被初始化。

char nome[] = "partidas.txt";
f = fopen(nome, "rt");
int size = fsize(f);

char **texto;
**texto = (char)malloc(size);

int i = 0;
while ((fgets(texto[i], sizeof(texto), f) != NULL))
{
  printf("%s\n", texto[i++]);
}

Answer 1

//remember to include the right header files

#include <stdio.h>
#include <string.h>
#include <errno.h>

#define READ_LENGTH 1024

char*      pFileContents = NULL;
int        iContentsIndex = 0;

long int   sz = 0;
FILE*      pFD = NULL;
int        readCount = 0;
int        stat = 0;

// note: all errors are printed on stderr, success is printed on stdout
// to find the size of the file:
// You need to seek to the end of the file and then ask for the position:

pFD = fopen( "filename", "rt" );
if( NULL == pFD )
{
    perror( "\nfopen file for read: %s", strerror(errno) );
    exit(1);
}

stat = fseek(pFD, 0L, SEEK_END);
if( 0 != stat )
{
    perror( "\nfseek to end of file: %s", strerror(errno) );
    exit(2);
}

sz = ftell(pFD);

// You can then seek back to the beginning
// in preparation for reading the file contents:

stat = fseek(pFD, 0L, SEEK_SET);
if( 0 != stat )
{
    perror( "\nfseek to start of file: %s", strerror(errno) );
    exit(2);
}

// Now that we have the size of the file we can allocate the needed memory
// this is a potential problem as there is only so much heap memory
// and a file can be most any size:

pFileContents = malloc( sz );
if( NULL == pFileContents ) 
{ 
    // handle this error and exit
    perror( "\nmalloc failed: %s", strerror(errno) );
    exit(3); 
}


// then you can perform the read loop
// note, the following reads directly into the malloc'd area

while( READ_LENGTH == 
       ( readCount = fread( pFileContents[iContentsIndex], READ_LENGTH, 1, pFD) ) 
     )
{
    iContentsIndex += readCount;
    readCount = 0;
}

if( (iContentsIndex+readCount) != sz )
{
    perror( "\nfread: end of file or read error", strerror(errno) );
    free( pFileContents );
    exit(4);
}

printf( "\nfile read successful\n" );

free( pFileContents );

return(0);

初始化动态数组c

1 个答案: