Temperature based fan speed control

#define triacPulse 10
#define SW 7
#define ZVC 2  //we can declare onlly pin 2 or 3 here because these both have interrupt read ability
int tempmax=50;
int tempmin=30;

int x = 0;
void setup()
{  Serial.begin(115200);
   pinMode(ZVC, INPUT_PULLUP);
   pinMode(A0, INPUT);
   pinMode(triacPulse, OUTPUT);
   pinMode(11,INPUT);
   pinMode(12,INPUT);
   pinMode(13,INPUT);
}
float temp()
  {  int val = analogRead(A0);
     float temp1 = ( val/1023.0)*500;
     return temp1;
   }
void pulse()
{ delayMicroseconds(x); // read AD0
  digitalWrite(triacPulse, HIGH);
  delayMicroseconds(50);  //delay 50 uSec on output pulse to turn on triac
  digitalWrite(triacPulse, LOW);
}
void pulse_for_min()
{ delayMicroseconds(7200); // read AD0
  digitalWrite(triacPulse, HIGH);
  delayMicroseconds(50);  //delay 50 uSec on output pulse to turn on triac
  digitalWrite(triacPulse, LOW);
}
void pulse_for_full()
{ delayMicroseconds(200); // read AD0
  digitalWrite(triacPulse, HIGH);
  delayMicroseconds(50);  //delay 50 uSec on output pulse to turn on triac
  digitalWrite(triacPulse, LOW);
}
void loop() {
  float temperature=temp(); 
  bool full_on = digitalRead(11);
  bool full_off = digitalRead(13);
  bool automatic = digitalRead(12);
    if(automatic==HIGH && full_on==LOW && full_off==LOW)
       {    if((temp >= tempmin) && (temp <= tempmax)) 
               {  // if temperature is higher than minimum temp & less than maximum temperature
                 int x = map(temp(), tempmin, tempmax,7200 ,200 );
                 Serial.println(digitalRead(ZVC));
                 attachInterrupt(0, pulse, FALLING); // attach Interrupt at PIN2
               }
           if(temp>=tempmax)
             pulse_for_full();
           if(temp<=tempmax)
              pulse_for_min();  
       }      
   if(automatic==LOW && full_on==HIGH && full_off==LOW)
        pulse_for_full();
   if(automatic==LOW && full_on==LOW && full_off==HIGH)
         pulse_for_min();

}