I have code where I use pointer functions to trigger different functions in the loop based on receiving the A and B keys from a keypad. However, when I run it on Tinkercad, it doesn’t work.

#include <Adafruit_LiquidCrystal.h>
#include <Keypad.h>
#include <math.h>

Adafruit_LiquidCrystal lcd(0);

const byte ROWS = 4;
const byte COLS = 4;

char keys[ROWS][COLS] = { 
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte rowPins[ROWS] = {9, 8, 7, 6}; 
byte colPins[COLS] = {5, 4, 3, 2}; 

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

String inputString = "";
int x1, y1, x2 = 0 , y2 = 0;
float x3, y3 ;
int OTDS, OTAZ;
bool firstCoordinateSet = false;
bool secondCoordinateSet = false;
bool OTAZ_Set = false;
bool OTDS_Set = false;
float angle;
float distance;

typedef void (*FunctionPointer)();
FunctionPointer selectedFunction; 

void functioncoord() {
  char key = keypad.getKey();

  if (key) {
    if (key == 'C') { 
      inputString = "";
      lcd.clear();
      firstCoordinateSet = false;
      secondCoordinateSet = false;
    } else if (key == '*') { 
      if (inputString.length() > 0) {
        inputString.remove(inputString.length() - 1);
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print(inputString);
      }
    } else if (key == 'A') { 
      if (inputString.length() == 8) {
        x1 = inputString.substring(0, 4).toInt();
        y1 = inputString.substring(4).toInt();
        inputString = "";
        lcd.clear();
        firstCoordinateSet = true;
        lcd.print("Target Coord Set");
        delay(1000);
        lcd.clear();
      }
    } else if (key == 'B') { 
       if (inputString.length() == 8) {
        x2 = inputString.substring(0, 4).toInt();
        y2 = inputString.substring(4).toInt();
        inputString = "";
        lcd.clear();
        secondCoordinateSet = true;
        lcd.print("Mortar Coord Set");
        delay(1000);
        lcd.clear();
      }
    } else if (key == '#') { 
      if (firstCoordinateSet) {
        calculate_A();
        lcd.setCursor(0, 0);
        lcd.print("Arg:");
        lcd.print(round((angle * 6400 / 360)));
        lcd.print(" mils");
        lcd.setCursor(0, 1);
        lcd.print("DS:");
        lcd.print(distance);
        lcd.print(" m");
      }
    } else {
      if (inputString.length() < 8) { 
        inputString += key;
      }
      String displayString = inputString;
      if (inputString.length() > 4) {
        displayString = inputString.substring(0, 4) + "," + inputString.substring(4);
      }

      lcd.setCursor(0, 0);
      lcd.print(displayString);
    }
  }
}

void functionangle() { 
  char key = keypad.getKey();

  if (key) {
    if (key == 'C') {
      inputString = "";
      lcd.clear();
      firstCoordinateSet = false;
      secondCoordinateSet = false;
      OTAZ_Set = false;
      OTDS_Set = false;
    } else if (key == '*') {
      if (inputString.length() > 0) {
        inputString.remove(inputString.length() - 1);
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print(inputString);
      }
    } else if (key == 'A') { 
      if (inputString.length() == 8) {
        if (!firstCoordinateSet) { 
          
          x1 = inputString.substring(0, 4).toInt();
          y1 = inputString.substring(4).toInt();
          inputString = "";
          lcd.clear();
          firstCoordinateSet = true;
          lcd.print("Observation Post");
          lcd.setCursor(0, 1);
          lcd.print("Coord Set");
          delay(1000);
          lcd.clear();
        } else if (firstCoordinateSet && !secondCoordinateSet) { 
         
          x2 = inputString.substring(0, 4).toInt();
          y2 = inputString.substring(4).toInt();
          inputString = "";
          lcd.clear();
          secondCoordinateSet = true;
          lcd.print("Mortar Coord Set");
          delay(1000);
          lcd.clear();
        }
      }
    } else if (key == 'B') {
      if (inputString.length() > 0 && !OTAZ_Set) {
        OTAZ = inputString.substring(0,8).toInt();
        inputString = "";
        lcd.clear();
        OTAZ_Set = true;
        lcd.print("OTAZ Set");
        delay(1000);
        lcd.clear();
      } else if (inputString.length() > 0 && OTAZ_Set && !OTDS_Set) {
        OTDS = inputString.substring(0,8).toInt();
        inputString = "";
        lcd.clear();
        OTDS_Set = true;
        lcd.print("OTDS Set");
        delay(1000);
        lcd.clear();
      }
    } else if (key == '#') { 
      if (firstCoordinateSet) {
        calculate_B();
        lcd.setCursor(0, 0);
        lcd.print("Arg:");
        lcd.print(round((angle * 6400 / 360)));
        lcd.print(" mils");
        lcd.setCursor(0, 1);

        lcd.print("DS:");
        lcd.print(distance);
        lcd.print(" m");
      }
    } else {
      if (inputString.length() < 8) {
        inputString += key;
      }
      String displayString = inputString;
      if (inputString.length() > 4) {
        displayString = inputString.substring(0, 4) + "," + inputString.substring(4);
      }

      lcd.setCursor(0, 0);
      lcd.print(displayString);
    }
  }
}

void setup() { 
  lcd.begin(16, 2);
  lcd.setBacklight(LOW);
  lcd.print("Mortar Calc");
  delay(1000);
  lcd.clear();

  while (!selectedFunction) { 
    char key = keypad.getKey();
    if (key) {
      inputString += key;
      lcd.print(inputString);
      if (key == 'A') { 
        selectedFunction = functioncoord;
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("SquareCoordinate");
        lcd.setCursor(0, 1);
        lcd.print("Method");
        delay(1500);
        inputString = "";
        lcd.clear();
      } else if (key == 'B') { 
        selectedFunction = functionangle;
        lcd.clear();
        lcd.setCursor(0, 0);
        lcd.print("Polar Method");
        delay(1500);
        inputString = "";
        lcd.clear();
      }
    }
  }
  
}

void loop() {
  if (selectedFunction) {
    selectedFunction();
  }
}

void calculate_A() {
  float deltaX = x1 - x2;
  float deltaY = y1 - y2;
  if (deltaX > 0 && deltaY > 0) { 
    angle = (180 + atan2(deltaX, deltaY) * (180 / PI));
  } else if (deltaX < 0 && deltaY < 0) { 
    angle = (180+atan2(-1*deltaX, -1*deltaY) * (180 / PI));
  } else if (deltaX > 0 && deltaY < 0) { 
    angle = (atan2(deltaX, deltaY) * (180 / PI));
  } else if (deltaX < 0 && deltaY > 0) { 
    angle = (180 - atan2(-1 * deltaX, -1 * deltaY) * (180 / PI));
  }
  
  distance = sqrt(pow(deltaX, 2) + pow(deltaY, 2))*10;

}

void calculate_B() { 
  x3 = (float)x1 + OTDS*sin((float)OTAZ*360/6400*PI/180)*0.1; 
  y3 = (float)y1 + OTDS*cos((float)OTAZ*360/6400*PI/180)*0.1; 
  float deltaX = x3 - (float)x2;
  float deltaY = y3 - (float)y2;
  if (deltaX > 0 && deltaY > 0) { 
    angle = (180 + atan2(deltaX, deltaY) * (180 / PI));
  } else if (deltaX < 0 && deltaY < 0) { /
    angle = (180+atan2(-1*deltaX, -1*deltaY) * (180 / PI));
  } else if (deltaX > 0 && deltaY < 0) { 
    angle = (atan2(deltaX, deltaY) * (180 / PI));
  } else if (deltaX < 0 && deltaY > 0) { 
    angle = (180 - atan2(-1 * deltaX, -1 * deltaY) * (180 / PI));
  }
  
  distance = sqrt(pow(deltaX, 2) + pow(deltaY, 2))*10; 
}

The error message is as follows: invalid headerflie

If I make one of the functions, either functionangle or functioncoord, an empty function, the code works fine. So, I suspect that the repeated content in both functions might be the cause. I have tried many different approaches over the past week, but I still can’t solve it. I really need your help!