1 读取文件
void main(){ char *path = "E:\\Test\\love.txt"; //打开 FILE *fp = fopen(path,"r"); if (fp==NULL){ printf("文件打开失败"); return; } //读取 char buff[50]; //缓冲 while (fgets(buff,50,fp)){ printf("%s",buff); } //关闭 fclose(fp); system("pause"); getchar(); }打印结果：
在那遥远的地方，有位好姑娘！2 写入文本文件
void main(){ char *path = "E:\\Test\\love.txt"; //打开 FILE *fp = fopen(path, "w"); char *text = "这街上太拥挤，太多人有秘密。玻璃上有雾气被吹散在房子里"; fputs(text, fp); //关闭流 fclose(fp); getchar(); }3 文件复制
void main(){ char *read_path = "E:\\Test\\liuyan.png"; char *write_path = "E:\\Test\\liuyan_copy.png"; //读取文件 b表示操作二进制文件binary FILE *read_fp = fopen(read_path,"rb"); //写的文件 FILE *write_fp = fopen(write_path,"wb"); //复制 int buff[50];//缓冲区域 int len = 0;//每次读到的数据长度 while ((len = fread(buff,sizeof(int),50,read_fp))!=0){ //将读到的内容写入新的文件 fwrite(buff,sizeof(int),len,write_fp); } //关闭流 fclose(read_fp); fclose(write_fp); getchar(); }4 获取文件大小
void main(){ char *read_path = "E:\\Test\\liuyan.png"; FILE *fp = fopen(read_path, "r"); //重新定位指针 //SEEK_END 文件末尾，0偏移量 fseek(fp, 0, SEEK_END); //返回当前的文件指针，相对于文件开头的位移量 long filesize = ftell(fp); printf("%d\n", filesize); getchar(); }5 文件加密解密
//加密 void crpypt(char normal_path[], char crypt_path[]){ //打开文件 FILE *normal_fp = fopen(normal_path, "r"); FILE *crypt_fp = fopen(crypt_path, "w"); //一次读取一个字符 int ch; while ((ch = fgetc(normal_fp)) != EOF){//end of file //写入（抑或运算） fputc(ch ^ 9, crypt_fp); } //关闭 fclose(crypt_fp); fclose(normal_fp); } //解密 void decrpypt(char crypt_path[], char decrypt_path[]){ //打开文件 FILE *normal_fp = fopen(crypt_path, "r"); FILE *crypt_fp = fopen(decrypt_path, "w"); //一次读取一个字符 int ch; while ((ch = fgetc(normal_fp)) != EOF){//end of file //写入（抑或运算） fputc(ch ^ 9, crypt_fp); } //关闭 fclose(crypt_fp); fclose(normal_fp); } void main(){ char *normal_path = "E:\\Test\\love.txt"; char *crypt_path = "E:\\Test\\love_crypt.txt"; char *decrypt_path = "E:\\Test\\love_decrypt.txt"; //加密 //crpypt(normal_path, crypt_path); //解密 decrpypt(crypt_path,decrypt_path); getchar(); }6 文件加密 解密（使用密码）
void crpypt(char normal_path[], char crypt_path[], char password[]){ //打开文件 FILE *normal_fp = fopen(normal_path, "rb"); FILE *crypt_fp = fopen(crypt_path, "wb"); //一次读取一个字符 int ch; int i = 0; //循环使用密码中的字母进行异或运算 int pwd_len = strlen(password); //密码的长度 while ((ch = fgetc(normal_fp)) != EOF){ //End of File //写入（异或运算） fputc(ch ^ password[i % pwd_len], crypt_fp); i++; } //关闭 fclose(crypt_fp); fclose(normal_fp); } //解密 void decrpypt(char crypt_path[], char decrypt_path[], char password[]){ //打开文件 FILE *normal_fp = fopen(crypt_path, "rb"); FILE *crypt_fp = fopen(decrypt_path, "wb"); //一次读取一个字符 int ch; int i = 0; //循环使用密码中的字母进行异或运算 int pwd_len = strlen(password); //密码的长度 while ((ch = fgetc(normal_fp)) != EOF){ //End of File //写入（异或运算） fputc(ch ^ password[i % pwd_len], crypt_fp); i++; } //关闭 fclose(crypt_fp); fclose(normal_fp); } void main(){ char *normal_path = "E:\\Test\\liuyan.png"; char *crypt_path = "E:\\Test\\crpt_liuyan.png"; char *decrypt_path = "E:\\Test\\decrpt_liuyan.png"; //crpypt(normal_path, crypt_path,"mima"); //解密 decrpypt(crypt_path, decrypt_path, "mima"); getchar(); }加密解密后：
