How do you write a program in C plus plus print 1 to 10000 in Roman numerals?

Answer 1

#include<iostream>

#include<sstream>

#include<exception>

std::string decimal_to_roman (unsigned num) {

std::stringstream ss {};

while (num>0) {

if (num>10000)

throw std::range_error (

"ERROR: decimal_to_roman (unsigned num) [num is out of range]");

else if (num==10000) { ss<<"[M]"; num-=10000; }

else if (num>=9000) { ss<<"[CM]"; num-=9000; }

else if (num>=5000) { ss<<"[D]"; num-=5000; }

else if (num>=4000) { ss<<"[CD]"; num-=4000; }

else if (num>=1000) { ss<<"M"; num-=1000; }

else if (num>=900) { ss<<"CM"; num-=900; }

else if (num>=500) { ss<<"D"; num-=500; }

else if (num>=400) { ss<<"CD"; num-=400; }

else if (num>=100) { ss<<"C"; num-=100; }

else if (num>=90) { ss<<"XC"; num-=90; }

else if (num>=50) { ss<<"L"; num-=50; }

else if (num>=40) { ss<<"XL"; num-=40; }

else if (num>=10) { ss<<"X"; num-=10; }

else if (num==9) { ss<<"IX"; num-=9; }

else if (num>=5) { ss<<"V"; num-=5; }

else if (num==4) { ss<<"IV"; num-=4; }

else if (num>=1) { ss<<"I"; num-=1; }

}

return ss.str();

}

int main (void) {

for (unsigned n=1; n<=10000; ++n) {

try {

std::cout << n << "\t = " << decimal_to_roman(n) << std::endl;

}

catch (std::range_error& e) {

std::cerr<<e.what()<<std::endl;

break;

}

}

}