gpio set

int GPIOClass::getval_gpio(string& val){

    string getval_str = "/sys/class/gpio/gpio" + this->gpionum + "/value";
    ifstream getvalgpio(getval_str.c_str());// open value file for gpio
    if (getvalgpio < 0){
        cout << " OPERATION FAILED: Unable to get value of GPIO"<< this->gpionum <<" ."<< endl;
        return -1;
            }

    getvalgpio >> val ;  //read gpio value

    if(val != "0")
        val = "1";
    else
        val = "0";

    getvalgpio.close(); //close the value file
    return 0;
}