Data commit

Task/Number-names/C/number-names.c

@@ -0,0 +1,137 @@
+#include <stdio.h>
+#include <string.h>
+
+const char *ones[] = { 0, "one", "two", "three", "four",
+	"five", "six", "seven", "eight", "nine",
+	"ten", "eleven", "twelve", "thirteen", "fourteen",
+	"fifteen", "sixteen", "seventeen", "eighteen", "nineteen" };
+const char *tens[] = { 0, "ten", "twenty", "thirty", "forty",
+	"fifty", "sixty", "seventy", "eighty", "ninety" };
+const char *llions[] = { 0, "thousand", "million", "billion", "trillion",
+//	"quadrillion", "quintillion", "sextillion", "septillion",
+//	"octillion", "nonillion", "decillion"
+	};
+const int maxillion = sizeof(llions) / sizeof(llions[0]) * 3 - 3;
+
+int say_hundred(const char *s, int len, int depth, int has_lead)
+{
+	int c[3], i;
+	for (i = -3; i < 0; i++) {
+		if (len + i >= 0) c[i + 3] = s[len + i] - '0';
+		else c[i + 3] = 0;
+	}
+	if (!(c[0] + c[1] + c[2])) return 0;
+
+	if (c[0]) {
+		printf("%s hundred", ones[c[0]]);
+		has_lead = 1;
+	}
+
+	if (has_lead && (c[1] || c[2]))
+		printf((!depth || c[0]) && (!c[0] || !c[1]) ? "and " :
+			c[0] ? " " : "");
+
+	if (c[1] < 2) {
+		if (c[1] || c[2]) printf("%s", ones[c[1] * 10 + c[2]]);
+	} else {
+		if (c[1]) {
+			printf("%s", tens[c[1]]);
+			if (c[2]) putchar('-');
+		}
+		if (c[2]) printf("%s", ones[c[2]]);
+	}
+
+	return 1;
+}
+
+int say_maxillion(const char *s, int len, int depth, int has_lead)
+{
+	int n = len / 3, r = len % 3;
+	if (!r) {
+		n--;
+		r = 3;
+	}
+	const char *e = s + r;
+	do {
+		if (say_hundred(s, r, n, has_lead) && n) {
+			has_lead = 1;
+			printf(" %s", llions[n]);
+			if (!depth) printf(", ");
+			else printf(" ");
+		}
+		s = e; e += 3;
+	} while (r = 3, n--);
+
+	return 1;
+}
+
+void say_number(const char *s)
+{
+	int len, i, got_sign = 0;
+
+	while (*s == ' ') s++;
+	if (*s < '0' || *s > '9') {
+		if (*s == '-') got_sign = -1;
+		else if (*s == '+') got_sign = 1;
+		else goto nan;
+		s++;
+	} else
+		got_sign = 1;
+
+	while (*s == '0') {
+		s++;
+		if (*s == '\0') {
+			printf("zero\n");
+			return;
+		}
+	}
+
+	len = strlen(s);
+	if (!len) goto nan;
+
+	for (i = 0; i < len; i++) {
+		if (s[i] < '0' || s[i] > '9') {
+			printf("(not a number)");
+			return;
+		}
+	}
+	if (got_sign == -1) printf("minus ");
+
+	int n = len / maxillion;
+	int r = len % maxillion;
+	if (!r) {
+		r = maxillion;
+		n--;
+	}
+
+	const char *end = s + len - n * maxillion;
+	int has_lead = 0;
+	do {
+		if ((has_lead = say_maxillion(s, r, n, has_lead))) {
+			for (i = 0; i < n; i++)
+				printf(" %s", llions[maxillion / 3]);
+			if (n) printf(", ");
+		}
+		n--;
+		r = maxillion;
+		s = end;
+		end += r;
+	} while (n >= 0);
+
+	printf("\n");
+	return;
+
+nan:	printf("not a number\n");
+	return;
+}
+
+int main()
+{
+	say_number("-42");
+	say_number("1984");
+	say_number("10000");
+	say_number("1024");
+	say_number("1001001001001");
+	say_number("123456789012345678901234567890123456789012345678900000001");
+	return 0;
+}