char toromai(int a) /* Arab számot alakít római számmá */
{
    int tmp,n=0;
    char romai[20];
    char error[10] = "#ÉRTÉK!";
    char egyesek[][10]  = {"I","II","III","IV","V","VI","VII","VIII","IX"};
    char tizesek[][10]  = {"X","XX","XXX","XL","L","LX","LXX","LXXX","XC"};
    char szazasok[][10] = {"C","CC","CCC","CD","D","DC","DCC","DCCC","CM"};
    char ezresek[][4]  = {"M","MM","MMM"};

    tmp=a;
    while(tmp>0)
    {
        tmp/=10;
        n++;
    }

    if(1<=a<4000)
    {
        romai[n]='\0';
        if(n==4)
        {
            strcat(romai,ezresek[(a/1000)-1]);
            a%=1000;
            n--;
        }
        if(n==3)
        {
            strcat(romai,szazasok[(a/100)-1]);
            a%=100;
            n--;
        }
        if(n==2)
        {
            strcat(romai,tizesek[(a/10)-1]);
            a%=10;
            n--;
        }
        else strcat(romai,egyesek[a-1]);

        return romai[20];
    }
    else return error[10];
}