int state_1 = 1;
int input_1 = digitalRead(PIN_1);
int output_1;

edge_detect(input_1,&state_1,&output_1);


void edge_detect(int input, int* button_state, int* output) {
    int theOutput = *output
    int bState = *button_state;
    if (bState == 1 && input == 0){
       theOutput = 1;
       bState = 0;
    }
    else if (bState == 0 && input == 1){
       theOutput = -1;
       bState = 1;
    }
    else{
       theOutput = 0;
    }
}