139 lines
3.1 KiB
C
139 lines
3.1 KiB
C
#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#define RDIGITS 14
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int validateN(char c) {
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int n = (int)c;
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return c > 47 && n < 58;
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}
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/*
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* Returns the value of a roman numeral digit
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* @param {char} c - Roman digit
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*/
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static int roman_to_integer(char c) {
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switch (c) {
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case 'I':
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return 1;
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case 'V':
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return 5;
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case 'X':
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return 10;
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case 'L':
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return 50;
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case 'C':
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return 100;
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case 'D':
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return 500;
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case 'M':
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return 1000;
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default:
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return 0;
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}
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}
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/*
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* Returns the interger value of a roman number
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* @param {string} s - Roman number
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*/
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int roman_to_int(char *s) {
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int i, int_num = roman_to_integer(s[0]);
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for (i = 1; s[i] != '\0'; i++) {
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int prev_num = roman_to_integer(s[i - 1]);
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int cur_num = roman_to_integer(s[i]);
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if (prev_num < cur_num) {
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int_num = int_num - prev_num + (cur_num - prev_num);
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} else {
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int_num += cur_num;
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}
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}
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return int_num;
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}
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/*
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* Map of roman digits symbols and their value
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* @elem {string} sym - digit symbol
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* @elem {int} val - digit symbol
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*/
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typedef struct {
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char *sym;
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int val;
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} numeral;
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/*
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* Returns greatest numeral index
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* @elem {numeral} nu - map of roman digits symbols and their value
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* @elem {int} num - number
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*/
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int maxNume(numeral *nu, int num) {
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int i, index;
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for (i = 0; i < RDIGITS; i++) { // RDIGITS numerals in array
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if (nu[i].val <= num)
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index = i;
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}
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// gretest value numeral index, not greater than number
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return index;
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}
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/*
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* Prints roman number from integer
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* @elem {numeral} nu - map of roman digits symbols and their value
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* @elem {int} num - number
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*/
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void decToRoman(numeral *nu, int num) {
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int max;
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if (num != 0) {
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max = maxNume(nu, num);
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printf("%s", nu[max].sym);
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num -= nu[max].val; // decrease number
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decToRoman(nu, num); // recursively print numerals
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}
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}
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/*
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* Main
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* @elem {int} argc - Argument count
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* @elem {string[]} argv - Strings array
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*/
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int main(int argc, char *argv[]) {
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int direction = 0;
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/*
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* 0: integer to roman (default)
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* 1: roman to integer
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*/
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for (int i = 0; i < argc; i++) {
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if (strcmp(argv[i], "-r")) {
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direction = 1;
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} else {
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direction = 0;
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}
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}
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numeral nume[RDIGITS] = {{"I", 1}, {"IV", 4}, {"V", 5}, {"IX", 9},
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{"X", 10}, {"XL", 40}, {"L", 50}, {"XC", 90},
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{"C", 100}, {"CD", 400}, {"D", 500}, {"CM", 900},
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{"M", 1000}, {"MMMM", 4000}};
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char str[51];
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int inputint = 0;
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switch (direction) {
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case 0:
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while (scanf("%50s", str) &&
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!feof(stdin)) // read integers and convert to roman
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{
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printf("%d\n", roman_to_int(str));
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scanf("%*[^\n]"); // discard all until newline
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}
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break;
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case 1:
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while (scanf("%9s", str) &&
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!feof(stdin)) // read roman and convert to integers
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{
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for (int i = 0; i < strlen(str); i++) {
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if (!validateN(str[i]))
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break;
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}
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sscanf(str, "%d", &inputint);
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decToRoman(nume, inputint);
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printf("\n");
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scanf("%*[^\n]"); // discard all until newline
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}
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break;
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}
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return 0;
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}
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