How to use LM35 Temerature Sensor

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

// Program states
// 0 - idle
// 1 - temperature data recording
// 2 - chart display

const int buttonPin = 2;   // The pin number for the button
const int lm35Pin = A0;

int CurrentState=0;
int temperatureValue ;
int numberOfReads=0;
unsigned long readTimestamp=0;
unsigned long buttonPress=0;


// Table to store time and temperature data
int data[50][2];
  
int dataSize ;
// Variables for scaling and labeling
int minX, maxX, minY, maxY;

void drawLineChart() {

  //dataSize=numberOfReads;
  
  // Calculate the scaling factors
  float scaleX = (float)(SCREEN_WIDTH - 20) / (maxX - minX);
  float scaleY = (float)(SCREEN_HEIGHT - 20) / (maxY - minY);

  // Draw X and Y axes
  display.drawLine(10, SCREEN_HEIGHT - 10 - 2, SCREEN_WIDTH - 10, SCREEN_HEIGHT - 10 - 2, WHITE);  // X axis
  display.drawLine(10, SCREEN_HEIGHT - 10 - 2, 10, 10 - 2, WHITE);                                  // Y axis

  // Draw X scale labels
  int numLabelsX = 5;  // Number of labels on the X axis
  int stepX = (maxX - minX) / (numLabelsX - 1);
  for (int i = 0; i < numLabelsX; i++) {
    int x = minX + i * stepX;
    int xPos = map(x, minX, maxX, 10, SCREEN_WIDTH - 10);
    display.setTextSize(1);
    display.setTextColor(WHITE);
    display.setCursor(xPos - 3, SCREEN_HEIGHT - 6 - 2);  // Move 2 pixels up
    display.print(x / 60);  // Convert seconds to minutes
  }

  // Draw Y scale labels
  int numLabelsY = 3;  // Number of labels on the Y axis
  int stepY = (maxY - minY) / (numLabelsY - 1);
  for (int i = 0; i < numLabelsY; i++) {
    int y = minY + i * stepY;
    int yPos = map(y, minY, maxY, SCREEN_HEIGHT - 10 - 2, 10 - 2);  // Move 2 pixels up
    display.setTextSize(1);
    display.setTextColor(WHITE);
    display.setCursor(1, yPos - 3 - 2);  // Move 2 pixels up
    display.print(int(y/10));
  }

  // Draw the line chart
  for (int i = 1; i < dataSize; i++) {
    int x1 = map(data[i - 1][0], minX, maxX, 10, SCREEN_WIDTH - 10);
    int y1 = map(data[i - 1][1], minY, maxY, SCREEN_HEIGHT - 10 - 2, 10 - 2);  // Move 2 pixels up
    int x2 = map(data[i][0], minX, maxX, 10, SCREEN_WIDTH - 10);
    int y2 = map(data[i][1], minY, maxY, SCREEN_HEIGHT - 10 - 2, 10 - 2);  // Move 2 pixels up
    display.drawLine(x1, y1, x2, y2, WHITE);
   // delay(500);
  }

  display.display();
}

void buttonInterrupt() {
  if (millis()-buttonPress>200){
  CurrentState++;
  if (CurrentState==3) CurrentState=0;
  buttonPress=millis();
  }
}

void setup() {
  Serial.begin(9600);
  pinMode(buttonPin, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(buttonPin), buttonInterrupt, FALLING);

  // Initialize the display
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.display();
  delay(2000);
  display.clearDisplay();
  display.display();

  // Find minimum and maximum values for scaling
  


}

void loop() {
  Serial.print("State:");Serial.print(CurrentState);Serial.print( "Reads:");Serial.println(numberOfReads);delay(1000);
  switch  (CurrentState)
  {
  case  0:
    //numberOfReads=0;
    display.clearDisplay();
    display.setTextSize(1);
    display.setCursor(1,1);
    display.setTextColor(WHITE);
    display.print("System Idle");
    display.display();
    break;  
    
    delay(1000);
  case 1:
    if (millis()-readTimestamp>60000 or readTimestamp==0){
      readTimestamp=millis();
      data[numberOfReads][0]=int(readTimestamp/1000);
      data[numberOfReads][1]= int((analogRead(lm35Pin) * 5.0 / 1023.0) * 1000.0);
      numberOfReads++;
      Serial.println(numberOfReads);
      display.clearDisplay();
      display.setTextSize(1);
      display.setCursor(1,1);
      display.setTextColor(WHITE);
      display.println("Reading Temperature");
      display.print("Number of reads: ");
      display.print(numberOfReads);
      display.display(); 
    }
  
    break;
  case  2:
     for (int i=0;i<dataSize;i++){Serial.print(data[i][0]);Serial.print("-"); Serial.println(data[i][1]);}
     dataSize = numberOfReads;
     minX = data[0][0];
     maxX = data[dataSize - 1][0];
     minY = maxY = data[0][1];
     for (int i = 1; i < dataSize; i++) {
      int x = data[i][0];
      int y = data[i][1];
      if (x < minX) minX = x;
      if (x > maxX) maxX = x;
      if (y < minY) minY = y;
      if (y > maxY) maxY = y;
    } 
    // Draw the line chart
    display.clearDisplay();
    display.display();
    drawLineChart();
    display.display();
    delay(1000);
    break;
  }
}