Adding blog post.

2021/11/30/Makefile

@@ -0,0 +1,4 @@
+convert : convert.cpp
+	c++ -O3 -Wall -Wextra -std=c++17 -o convert convert.cpp
+clean:
+	rm -r -f convert

2021/11/30/convert.cpp

@@ -0,0 +1,68 @@
+#include <iostream>
+#include <stdlib.h>
+#include <string>
+
+float parse1(const char *c) {
+  char *end;
+  return strtod(c, &end);
+}
+
+float parse2(const char *c) {
+  char *end;
+  return strtof(c, &end);
+}
+
+double parsed1(const char *c) {
+  char *end;
+  return strtod(c, &end);
+}
+
+double parsed2(const char *c) {
+  char *end;
+  return strtof(c, &end);
+}
+
+void demo() {
+  const char *test = "3.14159265358979323846264338327950";
+  if (parsed1(test) != parsed2(test)) {
+    std::cout << std::hexfloat;
+    std::cout << parsed1(test) << std::endl;
+    std::cout << parsed2(test) << std::endl;
+    std::cout.precision(200);
+    std::cout << std::fixed;
+    std::cout << parsed1(test) << std::endl;
+    std::cout << parsed2(test) << std::endl;
+    double x1 = parsed1(test);
+
+    double x2 = parsed2(test);
+    double x3 = 3.14159265358979323846264338327950;
+    std::cout << x3 - x1 << std::endl;
+    std::cout << x2 - x3 << std::endl;
+    std::cout << test << std::endl;
+  }
+}
+
+void demo2() {
+  const char *test = "0.004221370676532388";
+  if (parse1(test) != parse2(test)) {
+    std::cout << std::hexfloat;
+    std::cout << parse1(test) << std::endl;
+    std::cout << parse2(test) << std::endl;
+    std::cout.precision(200);
+    std::cout << std::fixed;
+    std::cout << parse1(test) << std::endl;
+    std::cout << parse2(test) << std::endl;
+    double x1 = parse1(test);
+
+    double x2 = parse2(test);
+    double x3 = 0.004221370676532388;
+    std::cout << x3 - x1 << std::endl;
+    std::cout << x2 - x3 << std::endl;
+    std::cout << test << std::endl;
+  }
+}
+
+int main() {
+  demo();
+  demo2();
+}