Save the date encoded file (gcc/g++)

Result:

Write file name:
 my_normal_with_date_file1
Write code file name:
 my_code_with_date_file1


------------------
(program exited with code: 0)
Press return to continue

cat my_normal_with_date_file1
Sat Jan 14 11:38:50 2017

cat my_code_with_date_file1
Qzu;Qzu;*(!*();*+)*;

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
using namespace std;

void init_Random()
{
    srand(time(NULL));
}
char *my_xor(char *text, char key)
{
    int i,j;
    char *temp_text=new char[48];
    j=strlen(text);
    for(i=0;i<j+1;i++)
     temp_text[i]=text[i]^key;
    return temp_text;
}
char *plus_text(char *text)
{
    int i,j;
    char *temp_text=new char[48];
    j=strlen(text);
    for(i=0;i<j+1;j++)
     temp_text[i]=255+text[i];
    return temp_text;
}
char *minus_text(char *text)
{
    int i,j;
    char *temp_text=new char[48];
    j=strlen(text);
    for(i=0;i<j+1;i++)
     temp_text[i]=255-text[i];
    return temp_text;
   
   
}
char *random_text(char *text)
{
    int i,j;
    i=rand()%3;
    char *temp_text;
    switch(i)
    {
        case 0: j=rand()%255; temp_text=my_xor(text,j);break;
        case 1: temp_text=plus_text(text);break;
        case 2: temp_text=minus_text(text);break;
    }
  return temp_text;
   
}
char *now_time()
{
    time_t n_time=time(NULL);
    return asctime(localtime(&n_time));
}
int main(int argc, char **argv)
{
    init_Random();
    char file_name[48],code_name[48];
    printf("Write file name:\n ");
    scanf("%s",file_name);
    printf("Write code file name:\n ");
    scanf("%s",code_name);
    char *time_text;
    char *code_text;
    time_text=now_time();
    code_text=random_text(time_text);
   
    int file_open;
    size_t file_length;
    file_length=strlen(time_text);
    file_open=open(file_name,O_WRONLY | O_CREAT | O_APPEND, 0666);
    write(file_open,time_text,file_length);
    close(file_open);
    FILE *next_file;
    next_file=fopen(code_name,"w");
    fprintf(next_file,"%s",code_text);
    fclose(next_file);
   

    return 0;
}