[Sync Iteration] c/say/1

solutions/c/say/1/say.c

@@ -0,0 +1,83 @@
+#include "say.h"
+#include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define ONE_BILLION ((int64_t)1000000000)
+#define RES_BUFFER_SIZE 1024
+
+static const char *ones[] = {
+    "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine"
+};
+
+static const char *teens[] = {
+    "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", 
+    "seventeen", "eighteen", "nineteen"
+};
+
+static const char *tens[] = {
+    "", "", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"
+};
+
+static const char *scales[] = {
+    "", "thousand", "million", "billion"
+};
+
+static void append_with_space(char *dest, const char *src) {
+    if (dest[0] != '\0') strcat(dest, " ");
+    strcat(dest, src);
+}
+
+static void process_chunk(int n, char *buf) {
+    if (n >= 100) {
+        append_with_space(buf, ones[n / 100]);
+        append_with_space(buf, "hundred");
+        n %= 100;
+    }
+    if (n >= 10 && n <= 19) {
+        append_with_space(buf, teens[n - 10]);
+    } else if (n >= 20) {
+        append_with_space(buf, tens[n / 10]);
+        if (n % 10 > 0) {
+            strcat(buf, "-");
+            strcat(buf, ones[n % 10]);
+        }
+    } else if (n > 0) {
+        append_with_space(buf, ones[n]);
+    }
+}
+int say(int64_t input, char **ans){
+    if (input < 0) return -1;
+    if (input > 999 * ONE_BILLION) return -1;
+
+    if (input == 0) {
+        (*ans) = malloc(sizeof("zero"));
+        if (!(*ans)) return -1;
+        strcpy(*ans, "zero");
+        return 0;
+    }
+
+    char result[RES_BUFFER_SIZE] = "";
+    int64_t divisor = ONE_BILLION;
+    int scale_idx = 3;
+
+    while (divisor > 0) {
+        int chunk = (input / divisor) % 1000;
+        if (chunk > 0) {
+            char chunk_buf[256] = "";
+            process_chunk(chunk, chunk_buf);
+            append_with_space(result, chunk_buf);
+            if (scale_idx > 0) {
+                append_with_space(result, scales[scale_idx]);
+            }
+        }
+        divisor /= 1000;
+        scale_idx--;
+    }
+
+    (*ans) = malloc(strlen(result) + 1);
+    if (!(*ans)) return -1;
+    strcpy(*ans, result);
+    return 0;
+}

solutions/c/say/1/say.h

@@ -0,0 +1,8 @@
+#ifndef SAY_H
+#define SAY_H
+
+#include <stdint.h>
+
+int say(int64_t input, char **ans);
+
+#endif