Fix extra arg consumption by %% (Fixes locutusjs#441)

* Fix extra arg consumption by %% (Fixes locutusjs#441)
* Add fixed example call

Author: paramsiddharth

src/c/stdio/sprintf.js

@@ -7,8 +7,11 @@ function pad (str, minLength, padChar, leftJustify) {
 
 module.exports = function sprintf (format, ...args) {
   // original by: Rafał Kukawski
+  // bugfixed by: Param Siddharth
   //   example 1: sprintf('%+10.*d', 5, 1)
   //   returns 1: '    +00001'
+  //   example 2: sprintf('%s is a %d%% %s %s.', 'Param', 90, 'good', 'boy')
+  //   returns 2: 'Param is a 90% good boy.'
   const placeholderRegex = /%(?:(\d+)\$)?([-+#0 ]*)(\*|\d+)?(?:\.(\*|\d*))?([\s\S])/g
 
   let index = 0
@@ -35,7 +38,11 @@ module.exports = function sprintf (format, ...args) {
 
     // compiling with default clang params, mixed positional and non-positional params
     // give only a warning
-    const arg = param ? args[param - 1] : args[index++]
+    const arg = param ? args[param - 1] : args[index]
+
+    if (modifier !== '%') {
+      index++
+    }
 
     if (precision === undefined || isNaN(precision)) {
       precision = 'eEfFgG'.includes(modifier) ? 6 : (modifier === 's' ? String(arg).length : undefined)