adding tests/strtod_test.c

tests/strtod_test.c

@@ -0,0 +1,28 @@
+#include "fast_float/fast_float_strtod.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+int main() {
+    // Test successful conversion
+    const char *str1 = "3.14159";
+    char *end1;
+    errno = 0;
+    double d1 = fast_float_strtod(str1, &end1);
+    printf("Input: %s\n", str1);
+    printf("Converted: %f\n", d1);
+    printf("End pointer: %s\n", end1);
+    printf("errno: %d\n", errno);
+
+    // Test invalid input
+    const char *str2 = "invalid";
+    char *end2;
+    errno = 0;
+    double d2 = fast_float_strtod(str2, &end2);
+    printf("\nInput: %s\n", str2);
+    printf("Converted: %f\n", d2);
+    printf("End pointer: %s\n", end2);
+    printf("errno: %d\n", errno);
+
+    return 0;
+}