//Roman to decimal, Decimal to Roman //by baptiste prunier //roman are from I = 1 to MMMCMXCIX = 3999 //after that, it is extended roman numeral //which this program does not support (as they are classical ones with a bar on them) //enter 0 for decimal or 1 for roman and then your value #include using namespace std; class Roman{ int decimal=0; string value; public: Roman(int n); Roman(string s); int getDec(); string getRom(); }; int main() { Roman *r; int n; string s; cin>>n; if(n){ cin>>s; r=new Roman(s); }else{ cin>>n; r=new Roman(n); } cout<getRom()<<" == "<getDec(); return 0; } Roman::Roman(string s){ int curr=s.length()-1,currC=6,power=1,iter; char c[]={'M','D','C','L','X','V','I'}; bool valid=true; value=s; while(curr>=0 && valid){ while(currC>=0 && s[curr]!=c[currC] && s[curr]!=c[currC]-'A'+'a' && (!currC || (s[curr]!=c[currC-1] && s[curr]!=c[currC-1]-'A'+'a'))){ currC-=2; power*=10; } if(currC>=0){ if(s[curr]==c[currC] || s[curr]==c[currC]-'A'+'a'){ iter=0; while(curr>=0 && iter<4 && (s[curr]==c[currC] || s[curr]==c[currC]-'A'+'a')){ decimal+=power; ++iter; --curr; } if(iter<4){ if(curr>=0 && (s[curr]==c[currC-1] || s[curr]==c[currC-1]-'A'+'a')){ decimal+=power*5; --curr; if(curr>=0 && currC<6 && (s[curr]==c[currC] || s[curr]==c[currC]-'A'+'a')){ decimal-=power; --curr; currC-=2; } }else if(curr>=0 && currC<5 && (s[curr]==c[currC+2] || s[curr]==c[currC+2]-'A'+'a')){ decimal-=(power/10); --curr; } }else{ valid=false; } }else{ decimal+=power*5; --curr; if(curr>=0 && currC<6 && (s[curr]==c[currC] || s[curr]==c[currC]-'A'+'a')){ decimal-=power; --curr; currC-=2; } } }else{ valid=false; } } if(valid){ value=s; }else{ decimal=0; value=*(new string("Undefined")); } } Roman::Roman(int n){ int power=1000, curr=0,val,currC=1; char roman[12]; char c[]={'M','D','C','L','X','V','I'}; if(n>0 && n<4000){ decimal=n; val=n/power; if(val){ while(val--){ roman[curr++]='M'; } } n%=power; power/=10; while(n){ val=n/power; if(val==9){ roman[curr++]=c[currC+1]; roman[curr++]=c[currC-1]; }else{ if(val){ if(val>=5){ roman[curr++]=c[currC]; val-=5; } if(val==4){ roman[curr++]=c[currC+1]; roman[curr++]=c[currC]; }else{ while(val--){ roman[curr++]=c[currC+1]; } } } } currC+=2; n%=power; power/=10; } roman[curr]=0; value=*(new string(roman)); }else{ value=*(new string("Undefined")); } } int Roman::getDec(){ return decimal; } string Roman::getRom(){ return value; }

Concertor : Decimal <=> Roman