fopen.c
#include <stdio.h>
int main() { // FILE *fp = fopen("abc", "rb+"); FILE *fp = fopen("abc", "ab+"); if (fp == NULL) { perror ("fopen"); return -1; } printf ("打开文件成功\n"); return 0;}
fread.c
#include <stdio.h> #define SIZE 1024 int main() { // FILE *fp = fopen("abc", "rb+"); FILE *fp = fopen("BTree.c", "ab+"); if (fp == NULL) { perror ("fopen"); return -1; } char buf[SIZE] = {0}; // feof 判断是否读到文件结尾，如果读到文件结尾，它返回一个非0 的值 int ret; while (ret = fread(buf, sizeof(char), SIZE-1, fp)) { buf[ret*sizeof(char)] = '\0'; printf ("%s\n", buf); } if(ret == 0 && !feof(fp)) { perror ("fread"); return -1; } printf ("文件读取结束\n"); return 0; }
fwrite.c
#include <stdio.h> #define SIZE 1024 int main() { // FILE *fp = fopen("abc", "rb+"); FILE *fp = fopen("1.ppt", "ab+"); if (fp == NULL) { perror ("fopen"); return -1; } FILE *fp1 = fopen("2.ppt", "ab+"); if (fp1 == NULL) { perror ("fopen"); return -1; } char buf[SIZE] = {0}; // feof 判断是否读到文件结尾，如果读到文件结尾，它返回一个非0 的值 int ret; while (ret = fread(buf, sizeof(char), SIZE, fp)) { fwrite(buf, sizeof(char), ret, fp1); } if(ret == 0 && !feof(fp)) { perror ("fread"); return -1; } printf ("文件读取结束\n"); fclose(fp); fclose(fp1); return 0; }
fgetc.c
#include <stdio.h> #define SIZE 1024 int main() { // FILE *fp = fopen("abc", "rb+"); FILE *fp = fopen("1.ppt", "ab+"); if (fp == NULL) { perror ("fopen"); return -1; } FILE *fp1 = fopen("2.ppt", "ab+"); if (fp1 == NULL) { perror ("fopen"); return -1; } char buf[SIZE] = {0}; // feof 判断是否读到文件结尾，如果读到文件结尾，它返回一个非0 的值 int ret; while (1) { int c = fgetc(fp); if (c == EOF) break; fputc(c, fp1); } fclose(fp); fclose(fp1); return 0; }
数据读取.c
#include <stdio.h> #define SIZE 1024 typedef struct student { int id; char name[20]; }STU; void write_data(STU *a) { FILE *fp = fopen("student", "ab+"); if (fp == NULL) { perror ("fopen"); return; } // 要写入个数 int len = sizeof(a)/sizeof(a[0]); fwrite(&len, sizeof(int), 1, fp); int i; for (i = 0; i < len; i++) { // 写入数据长度 len = sizeof(a[i]); fwrite(&len, sizeof(int), 1, fp); // 写入数据 fwrite(&a[i], sizeof(STU), 1, fp); } fclose(fp); } void read_data() { FILE *fp = fopen("student", "ab+"); if (fp == NULL) { perror ("fopen"); return; } // 读记录的个数 int count; fread (&count, sizeof(int), 1, fp); printf ("记录个数是：%d\n", count); int i; STU tmp; for (i = 0; i < count; i++) { int len; fread (&len, sizeof(int), 1, fp); // 读取数据 fread (&tmp, len, 1, fp); printf ("id = %d, name = %s\n", tmp.id, tmp.name); } fclose(fp); } int main() { int i; STU a[20]; for (i = 0; i < 20; i++) { a[i].id = i; sprintf (a[i].name, "zhang%d", i); } // 写入数据 // write_data(a); // 读数据 read_data(); return 0; }
