The original array is truncated after the copy function, why?

Question

C++ / C#

Write a program for encoding (decoding) text according
to the “complement” principle: in an English text, the letter a changes to the letter
z, the letter b changes to the letter y, the letter c changes to the letter x, etc.
And if it's not difficult, you can tell me how to pass the revers function to the crypt function.

#include <iostream>
#include <cstdlib>
#include <cmath>
#include <string.h>
#include <locale>
#include <cctype>
using namespace std;

void abc(char _abc[])
{
    int i,j = 0;
    for(int i = 97; i < 123;++i)
        _abc[j++] = (char)i;
    _abc[j] = '\0';
}

void revers(char _abc[])
{
   int temp;
   int i;
   for(i=0;i<strlen(_abc)/2;i++)
   {
       temp = _abc[i];
       _abc[i] = _abc[strlen(_abc)-i-1];
       _abc[strlen(_abc)-i-1] = temp;
   }

}
void crypt(char *msg,char *_abc,char* _abcReverse,char *cryptArray)
{
    int i,j;
    int index[strlen(msg)] ;
    for(i=0;i<strlen(msg);i++)
    {
        for(j=0;j < strlen(_abc);j++)

            {if (_abc[j] == msg[i]) index[i] = j;}
    }
    for(i=0;i<strlen(msg);i++) cout << index[i] << " "; // массив заполянется нулями


}
void out(char str[])
{
    for(int i = 0; i < strlen(str);i++) cout << str[i] << " ";
}
int main()
{
    char _abc[25]="";
    char _abcReverse[25] = "";
    char msg[] = "abc";
    char *crypArray = new char[strlen(msg)];
    abc(_abc);
    out(_abc);
    cout << endl;
    strcpy(_abcReverse,_abc); // после копирования масива исходный массив обрезается и в нём остаётся один символ
    revers(_abcReverse);
    out(_abcReverse);
    cout << endl;
    crypt(msg,_abc,_abcReverse,crypArray);
    cout << endl;
    system("pause");
    return 0;
}

Answer 1

#include <iostream>

void encode(char *msg)
{
    for (int i = 0; msg[i]; ++i)
    {
        msg[i] = 'z' - (msg[i] - 'a');
    }
}

int main()
{
    char msg[] = "hello";
    encode(msg);
    std::cout << msg << std::endl;
}

PS Don't use . It's not intended for what you're using it for. And should never be used at all. system("pause")

Answer 2

char _abc[25]="";
There are 26 letters in the Latin alphabet + a null character = 27. You have a classic buffer overflow. Most likely the extra letters are written into the memory of the _abcReverse array, and when _abcReverse was used for its intended purpose, the extra characters were overwritten.