Decriptare cifrul lui Cezar

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#include <iostream>
#include <string.h>

using namespace std;

char nr_lit[26] = {'a','b', 'c', 'd','e', 'f', 'g','h', 'i', 'j','k', 'l', 'm','n', 'o', 'p','q', 'r', 's','t', 'u',
    'v','w', 'x', 'y','z'};

int findposition(char a)
{
    int i = 0;
    for(i = 0; i < 26; i++)
    {
        if(a == nr_lit[i])
            break;
    }
    return i;
}

int main()
{

    char cuvant[45];
    int numar_modulo[45];
    cin>>cuvant;
    for(int k = 26; k >= 0; k--)
    {
        for(int i = 0; i <strlen(cuvant); i++)
        {
            if(cuvant[i] == 'a')
                cuvant[i] = 'z';
            else
                cuvant[i] = nr_lit[findposition(cuvant[i])-1];
            cout<<cuvant[i];
        }
        cout<<endl;
    }

    return 0;
}