Add string() methods to get the printable information

Author: saikishor

control_toolbox/include/control_toolbox/pid.hpp

@@ -146,6 +146,13 @@ struct AntiWindupStrategy
               << "\terror_deadband: " << error_deadband << std::endl;
   }
 
+  std::string string() const
+  {
+    return fmt::format(
+      "antiwindup_strat: {}\ti_max: {}\ti_min: {}\ttracking_time_constant: {}\terror_deadband: {}",
+      to_string(), i_max, i_min, tracking_time_constant, error_deadband);
+  }
+
   operator std::string() const { return to_string(); }
 
   constexpr bool operator==(Value other) const { return type == other; }
@@ -326,6 +333,13 @@ class Pid
       antiwindup_strat_.print();
     }
 
+    std::string string() const
+    {
+      return fmt::format(
+        "Gains(p: {}, i: {}, d: {}, u_max: {}, u_min: {}, antiwindup_strat: {})", p_gain_, i_gain_,
+        d_gain_, u_max_, u_min_, antiwindup_strat_.string());
+    }
+
     double p_gain_ = 0.0;                                     /**< Proportional gain. */
     double i_gain_ = 0.0;                                     /**< Integral gain. */
     double d_gain_ = 0.0;                                     /**< Derivative gain. */