C语言实现简单文件加密

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define KEY '@'
int main(int argc, char * argv[]){
FILE *fp;
FILE *coded;
char codedname[40];
char ch;
if(argc < 2){
printf("param error!\n");
exit(1);
}
if((fp = fopen(argv[1], "rb")) == NULL){
printf("error when open file %s.\n", argv[1]);
exit(1);
}
strcpy(codedname, argv[1]);
strcat(codedname, ".coded");
if((coded = fopen(codedname, "a+b")) == NULL){
printf("error when open file %s.\n", codedname);
exit(1);
}
while((ch = getc(fp)) != EOF){
char temp = ch^KEY;
putc(temp, coded);
}

if(fclose(fp) != 0){
printf("error when close file %s.\n", argv[1]);
exit(1);
}
if(fclose(coded) != 0){
printf("error when close file %s.\n", codedname);
}
return 0;
}

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main(int argc, char * argv[]){
FILE *fp;
FILE *decoded;
char decodedname[40];
char ch;
char key;
const char *dot = ".";
if(argc < 3){
printf("param error!\n");
exit(1);
}
if((fp = fopen(argv[1], "rb")) == NULL){
printf("error when open file %s.\n", argv[1]);
exit(1);
}
strcpy(decodedname, strtok(argv[1], dot));
strcat(decodedname, ".");
strcat(decodedname, strtok(NULL, dot));
key = argv[2][0];

if((decoded = fopen(decodedname, "a+b")) == NULL){
printf("error when open file %s.\n", decodedname);
exit(1);
}
while((ch = getc(fp)) != EOF){
char temp = ch^key;
putc(temp, decoded);
}

if(fclose(fp) != 0){
printf("error when close file %s.\n", argv[1]);
exit(1);
}
if(fclose(decoded) != 0){
printf("error when close file %s.\n", decodedname);
}
return 0;
}