How to use boolean function inside class in Arduino? - function

Question

I am making a library for the MPR121 sensor and in that I want to use a bool function inside a class in Arduino IDE but it is not working.
Here's my code.
#include <Wire.h>
#include "Adafruit_MPR121.h"
#ifndef _BV
#define _BV(bit) (1 << (bit))
#endif
Adafruit_MPR121 cap = Adafruit_MPR121();
uint16_t lasttouched = 0;
uint16_t currtouched = 0;
class PaperTron {
private:
uint8_t i;
uint8_t a;
public:
PaperTron(){
}
void touchBegin(){
Serial.begin(9600);
Serial.println("Hi! I'm PaperTron.");
if (!cap.begin(0x5A)) {
Serial.println("Error! TOUCH pins not found. Please check wiring.");
while (1);
}
Serial.println("Hurray! Now you can use my TOUCH pins.");
}
**//This is the boolean function which is not working**
bool isHigh(uint8_t touchpin) {
currtouched = cap.touched();
for (i=0; i<12; i++) {
if ((currtouched & _BV(i)) && !(lasttouched & _BV(i)) ) {
if(i==touchpin) return true;
}
if (!(currtouched & _BV(i)) && (lasttouched & _BV(i)) ) {
if(i==touchpin) return false;
}
}
lasttouched = currtouched;
}
};
PaperTron papertron;
void setup() {
papertron.Begin();
papertron.touchBegin();
}
void loop() {
if(papertron.isHigh(2)){Serial.println("Hello");}
}
The serial monitor is showing "Hello" continuously whereas it should print "Hello" only when I press the touch pin on MPR121.