# C > Mathematics Code Examples

## Program for Decimal to Roman Number conversion

``` Program for Decimal to Roman Number conversion #include<stdio.h> main() { int a,b,c,d,e; clrscr(); printf("Input a number (between 1-3000):"); scanf("%d",&e); while (e==0||e>3000) { printf ("ERROR: Invalid Input! "); printf ("Enter the number again:"); scanf ("%d",&e); } if (e>3000) printf("Invalid"); a = (e/1000)*1000; b = ((e/100)%10)*100; c = ((e/10)%10)*10; d = ((e/1)%10)*1; if (a ==1000) printf("M"); else if (a ==2000) printf("MM"); else if (a ==3000) printf("MMM"); if (b == 100) printf("C"); else if (b == 200) printf("CC"); else if (b == 300) printf("CCC"); else if (b == 400) printf("CD"); else if (b ==500) printf("D"); else if (b == 600) printf("DC"); else if (b == 700) printf("DCC"); else if (b ==800) printf("DCCC"); else if (b == 900) printf("CM"); if (c == 10) printf("X"); else if (c == 20) printf("XX"); else if (c == 30) printf("XXX"); else if (c == 40) printf("XL"); else if (c ==50) printf("L"); else if (c == 60) printf("LX"); else if (c == 70) printf("LXX"); else if (c ==80) printf("LXXX"); else if (c == 90) printf("XC"); if (d == 1) printf("I"); else if (d == 2) printf("II"); else if (d == 3) printf("III"); else if (d == 4) printf("IV"); else if (d ==5) printf("V"); else if (d == 6) printf("VI"); else if (d == 7) printf("VII"); else if (d ==8) printf("VIII"); else if (d == 9) printf("IX"); getch(); } ```