c - 需要有关fread()的帮助

Question

我正在尝试读取一个包含20个随机数的二进制文件。虽然文件似乎已读入，但是当我尝试将文件内容输出到屏幕时，我只会得到零。

我知道有20个数字，范围从1.00到9,999.99。任何帮助，将不胜感激！

#include <stdio.h>


int main()
{
    int i;          //counter
    FILE *file;     // file pointer
    double fileContents[20] = {0.0};

    file = fopen("numbers.bin", "rb"); // open resfile1.bin in read binary mode

    if (file == EOF)
    {
        printf("Error: Unable to open file.\n\n");
        exit(1);    // exit app
    }
    else
        printf("File successfully opened.\n\n");

    /**
        fileContents    = the array that holds the values read in from fread
        sizeof(double)     = the size of the data being read in 
        20              = the number of things to read in
        file            = the pointer to the file we've opened
    **/
    fread(fileContents, sizeof(double), 20, file);  // does nothing as far as I can tell

    for (i=0; i<20; i++)
        printf("%d: %lf\n", i, fileContents[i]);  // displays contents

    fclose(file);  // close file

    return 0;
}

Answer 1

我敢打赌，您不是在读取二进制文件。

尝试这个 ：

idx=0;
float fileContents[20] = {0.0};
while(!feof(file))    
    fscanf (file, "%f", &fileContents[idx++]);

for (i=0; i<idx; i++)
    printf("%d: %lf\n", i, fileContents[i]);

另外，请检查 if (file == NULL)是否打开失败。