Update numerical_methods/midpoint_integral_method.cpp

Co-authored-by: David Leal <halfpacho@gmail.com>

numerical_methods/midpoint_integral_method.cpp

@@ -15,6 +15,12 @@
  *
  * @author [ggkogkou](https://github.com/ggkogkou)
 */
+#include <iostream>          /// for IO operations
+#include <cmath>           /// for math functions
+#include <cassert>       /// for assert
+#include <cstdlib>     /// for std::atof
+#include <functional> /// for std::function
+#include <map>      /// for std::map container
 
 /**
  * @namespace numerical_methods