Documentation regarding the integer types

Author: lemire

README.md

@@ -4,17 +4,21 @@
 [![Ubuntu 22.04 CI (GCC 11)](https://github.com/fastfloat/fast_float/actions/workflows/ubuntu22.yml/badge.svg)](https://github.com/fastfloat/fast_float/actions/workflows/ubuntu22.yml)
 
 The fast_float library provides fast header-only implementations for the C++ from_chars
-functions for `float` and `double` types.  These functions convert ASCII strings representing
-decimal values (e.g., `1.3e10`) into binary types. We provide exact rounding (including
+functions for `float` and `double` types as well as integer types.  These functions convert ASCII strings representing decimal values (e.g., `1.3e10`) into binary types. We provide exact rounding (including
 round to even). In our experience, these `fast_float` functions many times faster than comparable number-parsing functions from existing C++ standard libraries.
 
-Specifically, `fast_float` provides the following two functions with a C++17-like syntax (the library itself only requires C++11):
+Specifically, `fast_float` provides the following two functions to parse floating-point numbers with a C++17-like syntax (the library itself only requires C++11):
 
 ```C++
 from_chars_result from_chars(const char* first, const char* last, float& value, ...);
 from_chars_result from_chars(const char* first, const char* last, double& value, ...);
 ```
 
+You can also parse integer types:
+
+
+
+
 The return type (`from_chars_result`) is defined as the struct:
 ```C++
 struct from_chars_result {
@@ -103,6 +107,43 @@ We support Visual Studio, macOS, Linux, freeBSD. We support big and little endia
 
 We assume that the rounding mode is set to nearest (`std::fegetround() == FE_TONEAREST`).
 
+
+## Integer types
+
+You can also parse integer types using different bases (e.g., 2, 10, 16). The following code will
+print the number 22250738585072012 three times:
+
+
+```C++
+  uint64_t i;
+  const char str[] = "22250738585072012";
+  auto answer = fast_float::from_chars(str, str + strlen(str), i);
+  if (answer.ec != std::errc()) {
+    std::cerr << "parsing failure\n";
+    return EXIT_FAILURE;
+  }
+  std::cout << "parsed the number "<< i << std::endl;
+
+  const char binstr[] = "1001111000011001110110111001001010110100111000110001100";
+
+  answer = fast_float::from_chars(binstr, binstr + strlen(binstr), i, 2);
+  if (answer.ec != std::errc()) {
+    std::cerr << "parsing failure\n";
+    return EXIT_FAILURE;
+  }
+  std::cout << "parsed the number "<< i << std::endl;
+
+
+  const char hexstr[] = "4f0cedc95a718c";
+
+  answer = fast_float::from_chars(hexstr, hexstr + strlen(hexstr), i, 16);
+  if (answer.ec != std::errc()) {
+    std::cerr << "parsing failure\n";
+    return EXIT_FAILURE;
+  }
+  std::cout << "parsed the number "<< i << std::endl;
+```
+
 ## C++20: compile-time evaluation (constexpr)
 
 In C++20, you may use `fast_float::from_chars` to parse strings