C语言中文件操作怎么实现C语言文件读写的基本步骤和示例

#include <stdio.h>

int main() {
  FILE *fp;

  // 打开文件用于写入
  fp = fopen("example.txt", "w");

  if (fp == NULL) {
    perror("Error opening file");
    return 1;
  }

  // 文件操作...

  fclose(fp); // 关闭文件
  return 0;
}

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

int main() {
  FILE *fp;
  char buffer[255];

  // 打开文件用于读取
  fp = fopen("example.txt", "r");

  if (fp == NULL) {
    perror("Error opening file");
    return 1;
  }

  // 使用 fgets 读取一行
  if(fgets(buffer, 255, fp) != NULL) {
    printf("%s", buffer);
  }

  fclose(fp);
  return 0;
}

#include <stdio.h>

int main() {
  FILE *fp;

  // 打开文件用于写入
  fp = fopen("example.txt", "w");

  if (fp == NULL) {
    perror("Error opening file");
    return 1;
  }

  // 使用 fprintf 写入格式化数据
  fprintf(fp, "This is a line of text.\n");

  fclose(fp);
  return 0;
}

#include <stdio.h>

int main() {
  FILE *fp;
  char ch;

  fp = fopen("nonexistent.txt", "r");

  if (fp == NULL) {
    perror("Error opening file");
    return 1;
  }

  while ((ch = fgetc(fp)) != EOF) {
    putchar(ch);
  }

  if (ferror(fp)) {
    perror("Error reading from file");
  } else if (feof(fp)) {
    printf("\nEnd of file reached.\n");
  }

  fclose(fp);
  return 0;
}

#include <stdio.h>

int main() {
  FILE *fp;
  int data[] = {1, 2, 3, 4, 5};
  int read_data[5];

  // 写入二进制数据
  fp = fopen("binary.dat", "wb");
  if (fp == NULL) {
    perror("Error opening file for writing");
    return 1;
  }
  fwrite(data, sizeof(int), 5, fp);
  fclose(fp);

  // 读取二进制数据
  fp = fopen("binary.dat", "rb");
  if (fp == NULL) {
    perror("Error opening file for reading");
    return 1;
  }
  fread(read_data, sizeof(int), 5, fp);
  fclose(fp);

  // 打印读取的数据
  for (int i = 0; i < 5; i++) {
    printf("%d ", read_data[i]);
  }
  printf("\n");

  return 0;
}

#include <stdio.h>

int main() {
  FILE *fp;

  fp = fopen("example.txt", "r");

  if (fp == NULL) {
    perror("Error opening file");
    return 1;
  }

  // 将文件指针移动到文件末尾
  fseek(fp, 0, SEEK_END);
  long file_size = ftell(fp); // 获取文件大小
  printf("File size: %ld bytes\n", file_size);

  // 将文件指针移动到文件开头
  fseek(fp, 0, SEEK_SET);

  fclose(fp);
  return 0;
}