C - 构建后打开文本文件 - OpenWRT - opkg

Question

我的 C 程序中有以下几行:

int main(int argc, char **argv) {    
  int i=0, p=0;

  FILE* fp;
  fp = fopen("jacina.txt", "w+");
  fscanf (fp, "%d", &i);

  if (ftruncate(fp, 0) == -1) {
    perror("Could not truncate")
  };

  p = i+10;
  fprintf(fp, "%d", p);
}

在 OpenWRT(来自 Ubuntu)中将此代码构建为 OPKG 后，我如何读取和写入位于该 OPKG 所在任何磁盘位置的文本文件？

Answer 1

Your code doesn't make any sense. To write the input given by user to a file:

Create a file first. Take input from user (say any string) and write it to the file with the help of file descriptor (fp) and close the file so that all buffers get flushed.

FILE *fp;
char comment[100] = {0};
 fp=fopen("tempfile.txt","w");

if (fp == NULL)
{
    printf("Error opening file!\n");
    exit(1);
}

printf("Enter String: ");
gets(comment);
fwrite(comment, sizeof(comment), 1, fp) ;

fclose(fp);

fprintf() too can be used instead to write data into a file.Similarly to read from a file you can use fgets() or fread() to store the contents of the file in a buffer and display the contents of the file. Hope it helps.