1、fseek,ftell,fread,fwrite(简单文件加密)
#define _CRT_SECURE_NO_WARNINGS //去掉安全检查
#include <stdio.h>
#include <stdlib.h>
/*读取文件大小*/
int getfilesize(char *path)
{
FILE *pf = fopen(path, "r");
if (pf == NULL)
{
fclose(pf);
return -1;
}
else
{
fseek(pf,0,SEEK_END);
int length = ftell(pf);
//获取文件大小
return length;
}
fclose(pf);
}
/*实现文件复制*/
void copy(char *oldpath,char *newpath)
{
FILE *pfr, *pfw;
//以打开二进制文件的方式打开
pfr = fopen(oldpath, "rb");
//写入二进制模式
pfw = fopen(newpath, "wb");
if (pfr == NULL || pfw == NULL)
{
fclose(pfr); //关闭文件
fclose(pfw);
return;
}
else
{
int length = getfilesize(oldpath);
//分配内存，读取文件
char *p = (char *)malloc(length * sizeof(char));
//读取二进制到内存
fread(p,sizeof(char),length,pfr);
//写入二进制到文件
fwrite(p,sizeof(char),length,pfw);
//关闭文件
fclose(pfr);
fclose(pfw);
}
}
void encryptyfile(char *oldpath,char *newpath)
{
FILE *pfr, *pfw;
pfr = fopen(oldpath, "rb");
//写入二进制模式
pfw = fopen(newpath, "wb");
if (pfr == NULL || pfw == NULL)
{
//关闭文件
fclose(pfr);
fclose(pfw);
return;
}
else
{
int length = getfilesize(oldpath);
//分配内存，读取文件
char *p = (char *)malloc(length*sizeof(char));
//读取二进制到内存
fread(p,sizeof(char),length,pfr);
for (int i = 0; i < length;i++)
{
//加密方法是，与制定字符进行异或操作
p[i] ^= 'A';
}
//写入二进制到文件
fwrite(p, sizeof(char), length, pfw);
//关闭文件
fclose(pfr);
fclose(pfw);
}
}
/*解密文件*/
void decodefile(char *oldpath,char *newpath)
{
FILE *pfr, *pfw;
pfr = fopen(oldpath, "rb");
//写入二进制模式
pfw = fopen(newpath,"wb");
if (pfr == NULL || pfw == NULL)
{
fclose(pfr);
fclose(pfw);
return;
}
else
{
int length = getfilesize(oldpath);
//分配内存，读取文件
char *p = (char *)malloc(length*sizeof(char));
//读取二进制到内存
fread(p,sizeof(char),length,pfr);
int i;
for (i = 0; i < length;i++)
{
p[i] ^= 'A';
}
//写入二进制到文件
fwrite(p, sizeof(char), length, pfw);
}
//关闭文件
fclose(pfr);
fclose(pfw);
}
int main(int argc,char *argv[])
{
char *path1 = "G:\\1.txt";
char *path2 = "G:\\2.txt";
char *path3 = "G:\\3.txt";
encryptyfile(path1, path2);
decodefile(path2, path3);
//printf("%d\n",getfilesize(path1));
system("pause");
return 0;
}
上面的过程将会把加解密的文件输出到文件中。
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
char jiami(char ch)
{
return ch ^ 123;
}
char jiemi(char ch)
{
return ch ^ 123;
}
void jia(char *path, char *pathjia)
{
FILE *pfr, *pfw;
pfr = fopen(path, "r");//读取
pfw = fopen(pathjia, "w");//写入
if (pfr == NULL || pfw == NULL)
{
fclose(pfw);
fclose(pfr);
return;
}
else
{
//feof(FILE *pf) 到了文件末尾1，没有到就是0
//下面的过程将把文件内容输出到屏幕上。
while (!feof(pfr))
{
//读取字符
char ch = fgetc(pfr);
putchar(ch);
//输出字符的时候将字符加密
fputc(jiami(ch), pfw);
}
}
fclose(pfr);
fclose(pfw);//关闭文件
}
/*解密*/
void jie(char *path,char *pathjie)
{
FILE *pfr, *pfw;
//读取
pfr = fopen(path, "r");
//写入
pfw = fopen(pathjie,"w");
if (pfr == NULL || pfw == NULL)
{
fclose(pfr);
fclose(pfw);
return;
}
else
{
//到了文件末尾1，没有到就是0
while (!feof(pfr))
{
char ch = fgetc(pfr);//读取字符
putchar(ch);
fputc(jiemi(ch), pfw);//写入一个加密的字符
}
}
fclose(pfr);
//关闭文件
fclose(pfw);
}
int main(int argc,char *argv[])
{
char *path1 = "G:\\1.txt";
char *path2 = "G:\\2.txt";
char *path3 = "G:\\3.txt";
//jia(path1, path2);
jie(path2, path3);
system("pause");
return 0;
}
密码加密
头文件：
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include<stdlib.h>
#include<string.h>
//字符串加密
char * stringjiami(char *password, char *string);
//字符串解密
char * stringjiemi(char *password, char *jiastring);
void filejiami(char *path, char *pathjia, char *password);
void filejiemi(char *pathjia, char *pathjie, char *password);
#include "encrytiondecrytion.h"
int getfilesize(char *path)
{
FILE *pf = fopen(path,"r");
if (pf == NULL)
{
return -1;
}
else
{
fseek(pf, 0, SEEK_END);//文件末尾
int length = ftell(pf);
return length;//返回长度
}
}
char * stringjiami(char *password, char *string)
{
//获取加密长度
int passlength = strlen(password);
//获取字符串长度
int stringlength = strlen(string);
if (stringlength % passlength == 0)
{
//循环次数
int ci = stringlength / passlength;
int i,j;
for (i = 0; i < ci;i++) //循环次数
{
//循环密码
for (j = 0; j < passlength;j++)
{
string[passlength*i + j] ^= password[j];
}
}
}
else
{
int ci = stringlength / passlength; //循环次数
int i, j;
for (int i = 0; i < ci;i++)
{
//循环密码
for (j = 0; j < passlength;j++)
{
string[passlength * i + j] ^= password[j];
}
}
int lastlength = stringlength % passlength;//剩下的长度
for (int i = 0; i < lastlength;i++)
{
string[passlength*(stringlength / passlength) + i] ^= password[i];
}
}
return string;
}
//字符串解密
char * stringjiemi(char *password, char *jiastring)
{
//获取加密长度
int passlength = strlen(password);
//获取字符串长度
int stringlength = strlen(jiastring);
if (stringlength %passlength == 0)
{
int ci = stringlength / passlength;//循环次数
int i, j;
for (i = 0; i < ci; i++)
{
for (j = 0; j < passlength;j++)
{
//异或加密
jiastring[passlength * i + j] ^= password[j];
}
}
}
else
{
//循环次数
int ci = stringlength / passlength;
int i, j;
for (i = 0; i < ci;i++)
{
//循环密码
for (j = 0; j < passlength;j++)
{
//异或加密
jiastring[passlength*i + j] ^= password[j];
}
}
//剩下的长度
int lastlength = stringlength % passlength;
for (int i = 0; j < lastlength;i++)
{
jiastring[passlength*(stringlength / passlength) + i] ^= password[i];
}
}
return jiastring;
}
void filejiami(char *path, char *pathjia, char *password)
{
FILE *pfr, *pfw;
pfr = fopen(path, "r");
pfw = fopen(pathjia,"w");
if (pfr == NULL || pfw == NULL)
{
fclose(pfr);
fclose(pfw);
return;
}
else
{
int length = getfilesize(path);
char *newstr = (char*)malloc(sizeof(char)*(length + 1));
for (int i = 0; i < length;i++)
{
char ch = fgetc(pfr); //获取一个字符
newstr[i] = ch;//不断存入字符
}
//字符串处理为'\0'
newstr[length] = '\0';
//加密字符串
stringjiami(password, newstr);
int i;
for (i = 0; i < length;i++)
{
//挨个写入字符
fputc(newstr[i], pfw);
}
}
fclose(pfr);
//关闭文件
fclose(pfw);
}
main.c
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include<stdlib.h>
#include "encrytiondecrytion.h"
int main(int argc,char *argv[])
{
char string[50] = "锄禾日当午";
char *password = "123";
printf("%s\n",stringjiami(password,string));
printf("%s\n", stringjiami(password, string));
char *path1 = "G:\\1.txt";
char *path2 = "G:\\2.txt";
char *path3 = "G:\\3.txt";
filejiami(path1, path2, "ABCDE");
filejiami(path2, path3, "ABCDE");
system("pause");
}
fscanf
#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
int main(int argc, char *argv[])
{
char str[100] = { 0 };
fscanf(stdin, "%s", str);
fprintf(stdout, "str=%s\n", str);
system(str);
return 0;
}
