Hi i am making a program with a counter, i was wondering how you can reset it

sorry about not being clear what I am trying to measure RPM using a QRD1114 and I can get record how many times the axle goes round but i need the count to reset to 0 every second so i can work out the RPM this is my program:

#include "mbed.h"
#include "TextLCD.h"

class Counter {
public:
    Counter(PinName p18) : _interrupt(p18) {       
        _interrupt.rise(this, &Counter::increment);
    }

    void increment() {
        _count++;
    }

    int read() {
        return _count;
count_reset
    }

private:
    InterruptIn _interrupt;
    volatile int _count;
  
};

Counter counter(p18);

int main() {
    TextLCD lcd(p24, p25, p26, p27, p28, p29, p30); // rs, rw, e, d0, d1, d2, d3
    while(1) {
        lcd.printf("Count so far:\n %d\n", counter.read());
       
       
    }
}

the "count_reset" is not ment to be in it.

Thanks for your help.