Serial problem after implementing data structures

Question

Context

I first ran a sketch (on Arduino Uno) without any custom data structure and list, so I was using a bunch of arrays, methods and other primitive variables. And it worked perfectly.

My program acts like a menu which takes serial user input to perform actions. So you could have serial input "man r+(100,0,345)". Or just "man" to set this mode active, and later "r+(100,0,345)" to actualize the data in the "r" field in the "man" instance. I use a custom data structure to manage the input (class called Mode), and a linked list (class called ModeList).

Problem

I implemented some data structures (an object and a list) to manage incoming serial data, without modifying the rest of the program. But now, serial communication is not working properly: If I add Serial.print("Allo") anywhere in the sketch, it will print spaces for a while and stop, before I send any serial data. If it is in the setup() function, it prints spaces continuously with some characters from "Allo" from time to time. There's always a different problem along those lines, depending on where I put that simple print statement.

Here follows the sketch, the header files of the Mode and ModeList classes... By the way, I suspect a memory management problem.

The sketch

#include "Mode.h"
#include "ModeList.h"
const int inputSize=12;
const int nbModes=4;
int input;
int toSet[inputSize];
int i;
char manName[3]={'m','a','n'};
char cutName[3]={'c','u','t'};
char levName[3]={'l','e','v'};
char autName[3]={'a','u','t'};
Mode m=Mode(0,manName);
Mode c=Mode(1,cutName);
Mode l=Mode(2,levName);
Mode a=Mode(3,autName);
Mode* man=&m;
Mode* cut=&c;
Mode* lev=&l;
Mode* aut=&a;
ModeList modeList=ModeList();
void setup() {
 Serial.begin(115200);
 Serial.print("Allo");
 modeList.add(man);
 modeList.add(cut);
 modeList.add(lev);
 modeList.add(aut);
 }
void loop() {
 for(int j=0;j<inputSize;j++)
 {
 toSet[j]=NULL;
 }
 i=0;
 if(Serial.available()>0)
 {
 while(Serial.available())
 {
 if(i<inputSize)
 {
 input=Serial.read();
 if(input!=' ' && input!='(' && input !=')' && input!=',' && input!='\n')
 {
 toSet[i]=input;
 i++;
 }
 }
 }
 }
 if(serialMode(man)||man->getStatus())
 {
 //Set man on
 modeList.setMode(man);
 if(toSet[3]=='r')
 {
 if(toSet[4]=='+')
 {
 //Set ypr rate
 Serial.println("Set ypr rate +");
 }
 else if(toSet[4]=='-')
 {
 //Set ypr rate
 Serial.println("Set ypr rate -");
 }
 else
 {
 //Set ypr rate
 Serial.println("Set ypr rate");
 }
 }
 else if(toSet[3]=='a')
 {
 if(toSet[4]=='+')
 {
 //Set ypr angle
 Serial.println("Set ypr angle +");
 }
 else if(toSet[4]=='-')
 {
 //Set ypr angle
 Serial.println("Set ypr angle -");
 }
 else
 {
 //Set ypr angle
 Serial.println("Set ypr angle");
 }
 }
 else if(toSet[3]=='t')
 {
 if(toSet[4]=='+')
 {
 //Set thrust
 Serial.println("Set thrust +");
 }
 else if(toSet[4]=='-')
 {
 //Set thrust
 Serial.println("Set thrust -");
 }
 else
 {
 //Set thrust
 Serial.println("Set thrust");
 }
 }
 }
 if(serialMode(cut)||cut->getStatus())
 {
 //Cut engines
 modeList.setMode(cut);
 if(serialMode(cut))
 Serial.println("Cut");
 }
 if(serialMode(lev)||lev->getStatus())
 {
 //Stabilize axes
 modeList.setMode(lev);
 if(serialMode(lev))
 Serial.println("Level");
 }
 if(serialMode(aut)||aut->getStatus())
 {
 //Set aut on
 modeList.setMode(aut);
 if(serialMode(aut))
 Serial.println("Set aut on");
 if(toSet[3]=='s')
 {
 if(toSet[4]=='+')
 {
 //Set ypr angle
 Serial.println("Set ypr angle +");
 }
 else if(toSet[4]=='-')
 {
 //Set ypr angle
 Serial.println("Set ypr angle -");
 }
 else
 {
 //Set ypr angle
 Serial.println("Set ypr angle");
 }
 }
 else if(toSet[3]=='A')
 {
 if(toSet[4]=='+')
 {
 //Set altitude
 Serial.println("Set altitude +");
 }
 else if(toSet[4]=='-')
 {
 //Set altitude
 Serial.println("Set altitude -");
 }
 else
 {
 //Set altitude
 Serial.println("Set altitude");
 }
 }
 }
 delay(10);
}
bool serialMode(Mode* inputMode)
{
 char* modeName;
 modeName=inputMode->getName();
 Serial.print("ALLO");
 if(toSet[0]==*modeName&&toSet[1]==*(modeName+1)&&toSet[2]==*(modeName+2))
 {
 Serial.print("Set ");
 for(int i=0;i<3;i++)
 {
 Serial.print(*(modeName+i));
 }
 Serial.println(" on");
 return true;
 }
 else
 return false;
}

The Mode class header

#include "Arduino.h"
class Mode
{
 public:
 Mode(int id, char* name);
 int getId();
 Mode* getNext();
 void setNext(Mode m);
 void setStatus(bool status);
 bool getStatus();
 char* getName();
 private:
 char *_name;
 int _id;
 Mode* _next;
 bool _status;
};

The ModeList class header

class ModeList
{
 public:
 void add(Mode* input);
 int get(int pos);
 ModeList();
 void setMode(Mode* inputMode);
 private:
 Mode* start;
 Mode* end;
};

Answer 1

If I add Serial.print("Allo") anywhere in the sketch, it will print spaces for a while and stop, before I send any serial data.

Classic symptoms of using up all available RAM.

As a workaround I would use the F() macro.

eg.

 Serial.println(F("Set ypr rate +"));

Do that in all places where you are printing string literals. That would save you a couple of hundred bytes.