Help with a little timer

Using Arduino Programming Questions
#1

Hello and good morning everyone, i'm having a bit of a trouble to get a small "timer" to work, and since i'm a bit new to c++ (and programming in general) i'm having a hard time figuring it out. So, i'm using a 4 digits led-display with a temperature sensor (lm35 sensor). I got the sensor to work with the led-display, but it's hard to read because how often the temperature slightly changes. So i decided to use a small "timer" to read the temperature once in a while and here it appeared the problem, i cant get the "timer" to work.
Here is my code

#include "SevSeg.h"
float tempC;
int tempPin = 0; 
float time1;

SevSeg sevseg; //Initiate a seven segment controller object

void setup() {

Serial.begin(9600);

byte numDigits = 4;

byte digitPins[] = {2, 3, 4, 5};

byte segmentPins[] = {6, 7, 8, 9, 10, 11, 12, 13};

bool resistorsOnSegments = false;

byte hardwareConfig = COMMON_CATHODE;

sevseg.begin(hardwareConfig, numDigits, digitPins, segmentPins, resistorsOnSegments);

sevseg.setBrightness(90);

}

void loop() {
time1 + 1;
if (time1 == 100); {
  tempC = analogRead(tempPin); 
  tempC = (5.0 * tempC * 100.0)/1024.0;
  sevseg.setNumber(tempC, 1);
  time1 = 0;
}

sevseg.refreshDisplay(); // Must run repeatedly

Serial.println(tempC);

Serial.println(time1);


}

Any help is appreciated.

PD: Sorry for bad spelling issues/wrong words

#2 
time1 + 1;

Adding one to time1, but not storing the new value anywhere is pointless.

if (time1 == 100); {

Can you find ONE other example that uses a ; on the if statement AND curly braces?

#3