Roman to integer

Signed-off-by: begeekmyfriend <[email protected]>

Author: begeekmyfriend

013_roman_numeral/Makefile renamed to 012_roman_numeral/Makefile

@@ -0,0 +1,2 @@
+all:
+	gcc -O2 -o test roman_to_integer.c

013_roman_numeral/roman_numeral.c renamed to 012_roman_numeral/roman_numeral.c

@@ -0,0 +1,50 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+static int roman_to_integer(char c)
+{
+    switch(c) {
+    case 'I':  
+        return 1;  
+    case 'V':  
+        return 5;  
+    case 'X':  
+        return 10;  
+    case 'L':  
+        return 50;  
+    case 'C':  
+        return 100;  
+    case 'D':  
+        return 500;  
+    case 'M':  
+        return 1000;  
+    default:
+        return;
+    }
+}
+
+int romanToInt (char *s) {
+    int i, result = roman_to_integer(s[0]);
+
+    for (i = 1; s[i] != '\0'; i++) {
+        int prev = roman_to_integer(s[i - 1]);
+        int curr = roman_to_integer(s[i]);
+        //if left<right such as : IV(4), XL(40), IX(9) ...
+        if (prev < curr) {
+            result = result - prev + (curr - prev);
+        } else {
+            result += curr;
+        }
+    }
+
+    return result;
+}
+int main(int argc, char **argv)
+{
+    if (argc < 2) {
+        fprintf(stderr, "Usage: ./test roman\n");
+        exit(-1);
+    }
+    printf("%d\n", romanToInt(argv[1]));
+    return 0;
+}