Integer to Roman using C program

 

Integer to Roman Conversion 

Using C program

Program for converting Integer to equivalent Roman:

C Program:

#include<stdio.h> #include<conio.h> void main() { int num,i; printf("Enter the Integer:"); scanf("%d",&num);//get the input from the user int a[] = {1,4,5,9,10,40,50,90,100,400,500,900,1000}; char sym[][20] = {"I","IV","V","IX","X","XL","L","XC","C","CD","D","CM","M"}; printf("The equivalent Roman Number:"); for(i=12;i>=0;i--) { int div = num/a[i]; num= num%a[i]; while(div--) { printf("%s",sym[i]); } } }

Output 1:

Explanation:     

SYMBOL	VALUE
I	1
IV	4
V	5
IX	9
X	10
XL	40
L	50
XC	90
C	100
CD	400
D	500
CM	900
M	1000

consider the above table,

ü Symbol values are stored in the array sym[][20] and value are stored in the array a[].

ü a[j] is the character to be compared with a[i].

ü For loop is used for the iteration. since symbol are 13 values, i value starts with 12 to perform the loop with larger value then moving to the smaller value till '0'.

for(i=12;i>=0;i--) { int div = num/a[i]; num= num%a[i]; while(div--) { printf("%s",sym[i]); } }

ü Let's consider 36 for num.

Process is described below in the  table,

ITERATIONS	i	i>=0	div=num/a[i]	num=num%a[i]	While (div--)	Print sym[i]	i--
1st iteration	12	12>=0 true	div=36/a[12] div=36/1000 div=0	num=36%a[12] num=36%1000 num=36	While(0--) false	Does not execute	11
2nd iteration	11	11>=0 true	div=36/a[11] div=36/900 div=0	num=36%a[11] num=36%900 num=36	While(0--) false	Does not execute	10
3rd iteration	10	10>=0 true	div=36/a[10] div=36/500 div=0	num=36%a[10] num=36%500 num=36	While(0--) false	Does not execute	9
4th  iteration	9	9>=0 true	div=36/a[9] div=36/400 div=0	num=36%a[9] num=36%400 num=36	While(0--) false	Does not execute	8
5th iteration	8	8>=0 true	div=36/a[8] div=36/100 div=0	num=36%a[8] num=36%100 num=36	While(0--) false	Does not execute	7
6th  iteration	7	7>=0 true	div=36/a[7] div=36/90 div=0	num=36%a[7] num=36%90 num=36	While(0--) false	Does not execute	6
7th  iteration	6	6>=0 true	div=36/a[6] div=36/50 div=0	num=36%a[6] num=36%50 num=36	While(0--) false	Does not execute	5
8th  iteration	5	5>=0 true	div=36/a[5] div=36/40 div=0	num=36%a[5] num=36%40 num=36	While(0--) false	Does not execute	4
9th  iteration	4	4>=0 true	div=36/a[4] div=36/10 div=3	num=36%a[4] num=36%10 num=6	While(3--) true	Sym[4] Print X
					While(2--) true	Sym[4] Print X
					While(1--) true	Sym[4] Print X
					While(0--) false	Does not execute	3
10th  iteration	3	3>=0 true	div=6/a[3] div=6/9 div=0	num=6%a[3] num=6%9 num=6	While(0--) false	Does not execute	2
11th  iteration	2	2>=0 true	div=36/a[2] div=6/5 div=1	num=6%a[2] num=6%5 num=1	While(1--) true	Sym[2] Print V
					While(0--) false	Does not execute	1
12th  iteration	1	1>=0 true	div=1/a[1] div=1/4 div=0	num=1%a[1] num=1%4 num=1	While(0--) false	Does not execute	0
13th  iteration	0	0>=0 true	div=1/a[0] div=1/1 div=1	num=1%a[0] num=1%1 num=0	While(1--) true	Sym[0] Print I
					While(0--) false	Does not execute	-1
14th  iteration	-1	-1>=0 false	Comes out of the loop

ü Thus the final output will be as XXXVI.

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