Question

我有一个包含矩阵N乘3浮点数的文本文件。我需要读取矩阵并将数据放入动态分配的数组中。我有以下代码：

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

#define X_ 0
#define Y_ 0
#define Z_ 0
#define VERTEX_COUNT 3


void read_data(FILE* FILE_POINTER, float **GRID, int N_LINES)
{
int i = 0, j=0;

for(i = 0; i < N_LINES; i++)
{
  for(j = 0; j < VERTEX_COUNT; j++) 
  {
   if (!fscanf(FILE_POINTER, "%f", &GRID[i][j])) 
       break;
  }

}
}



int find_length(FILE* FILE_POINTER)
{
int ch = 0;
int length = 0;

if(FILE_POINTER != NULL)
{
    while(!feof(FILE_POINTER))
    {
        ch = fgetc(FILE_POINTER);
        if(ch == '\n')
        {
            length++;
        }
    }
}
else
{
    perror("File not found");
    exit(EXIT_FAILURE);
} 
return length;
}



int main() 
{   
/* Define variables needed*/
int i=0,j=0;
float** GRID_GEOM;
float** GRID_TOPO;

/* Open the files containing the data*/
FILE* FILE_GEOM = fopen("temporary_geom.txt","r");
FILE* FILE_TOPO = fopen("temporary_topo.txt","r");

/* Find length of the data set*/
int N_POINTS = find_length(FILE_GEOM);
int N_TRIANG = find_length(FILE_TOPO);


/* Dynamically allocate memory for each data set*/
GRID_GEOM = malloc(N_POINTS * sizeof(float*));
for (i = 0; i < N_POINTS; i++)
{
    GRID_GEOM[i] = malloc(VERTEX_COUNT * sizeof(float));
}

GRID_TOPO = malloc(N_TRIANG * sizeof(float*));
for (i = 0; i < N_TRIANG; i++)
{
    GRID_TOPO[i] = malloc(VERTEX_COUNT * sizeof(float));
}

/* Read data into the arrays*/
read_data(FILE_GEOM, GRID_GEOM, N_POINTS);


/* Close the files */
fclose(FILE_GEOM);
fclose(FILE_TOPO);

/* Free the memory allocated */
for (i = 0; i < N_POINTS; i++) 
{
    free(GRID_GEOM[i]);
}
free(GRID_GEOM);

for (i = 0; i < N_TRIANG; i++) 
{
    free(GRID_TOPO[i]);
}
free(GRID_TOPO);
}

当我尝试访问矩阵GRID_GEOM中的任何位置时，所有值似乎都为0.我无法弄清楚原因。

Answer 1

在函数$ rails dev:cache Development mode is now being cached.中，您读取整个文件，因此当您将文件指针传递给find_length时，它已指向它的末尾。

您可以rewind the pointer，也可以关闭文件并重新打开以解析数据。

读写动态分配的数组

1 个答案: