#include <stdio.h> 
#include <stdlib.h> 
/* 
  該代碼是對文件讀寫操作的使用 
*/ 
#pragma warning(disable:4996) 
#define MAX_DATA_LEN 4096 
//進(jìn)行加密的函數(shù) 
int FileSymEnc(char * from, char * to); 
 
void main() { 
 
  char * from = "C:/Users/Administrator/Desktop/結(jié)構(gòu)體的拷貝問題.docx"; 
  char * to = "C:/Users/Administrator/Desktop/副本結(jié)構(gòu)體的拷貝問題.docx"; 
  //下面調(diào)用函數(shù)進(jìn)行文件的讀寫 
  int re = FileSymEnc(from, to); 
  if (re == 0) { 
    printf("文件讀寫錯誤！"); 
  } 
  system("pause"); 
} 
 
int FileSymEnc(char * from, char * to) { 
  //返回值，以確定執(zhí)行狀態(tài),-0代表失敗,1代表成功 
  int re = 1; 
  //寫了幾個 
  int writtenLen = 0; 
  //準(zhǔn)備寫幾個 
  int plainlen = 0; 
  //在堆區(qū)分配4k內(nèi)存空間 
  unsigned char * buff = malloc(MAX_DATA_LEN); 
  buff = memset(buff, 0, MAX_DATA_LEN); 
  FILE * f = fopen(from, "rb"); 
  FILE * t = fopen(to, "wb"); 
  if (f == NULL) { 
    printf("打開讀文件錯誤！"); 
    goto END; 
  } 
  if (t == NULL) { 
    printf("打開寫文件錯誤！"); 
    goto END; 
  } 
 
  while (!feof(f)) 
  { 
 
    writtenLen = fread(buff, 1, MAX_DATA_LEN, f); 
    //判讀是否讀到了文件末尾，如果讀到了則跳出循環(huán) 
    if (feof(f)) 
    { 
      plainlen = writtenLen; 
      break; 
    } 
 
    if (writtenLen != MAX_DATA_LEN) { 
      //沒有讀取成功 
      printf("文件讀入失敗！"); 
      re = 0; 
      goto END; 
    } 
    //讀取成功進(jìn)行文件的寫入 
    writtenLen = fwrite(buff, 1, MAX_DATA_LEN, t); 
    if (writtenLen != MAX_DATA_LEN) { 
      printf("文件寫入失敗！"); 
      re = 0; 
      goto END; 
    } 
  } 
 
  //外面處理不到4K的寫入問題，我們本不用進(jìn)行格外的小數(shù)據(jù)讀寫，主不過這和我們的加密方式相關(guān)連得 
  writtenLen = fwrite(buff, 1, plainlen, t); 
  if (writtenLen != plainlen) { 
    printf("文件寫入失??！"); 
    re = 0; 
    goto END; 
  } 
 
END: 
  //堆分配的內(nèi)存進(jìn)行釋放 
  if (buff != NULL) { 
    free(buff); 
    buff = NULL; 
  } 
  //進(jìn)行文件的關(guān)閉操作 
 
  if (f != NULL) { 
    fclose(f); 
    f = NULL; 
  } 
  if (t != NULL) { 
    fclose(t); 
    f = NULL; 
  } 
  return re; 
}