Raspberry Pi 4 CPU temperature monitoring (Ubuntu Server LTS 20.04)

tmonit.c

#include <stdio.h>
#include <unistd.h>

int main(int argc, char *argv[]) 
{
   FILE *fp;

   while(1) 
   {
      int temp = 0;
      fp = fopen("/sys/class/thermal/thermal_zone0/temp", "r");
      fscanf(fp, "%d", &temp);
      printf(">> CPU Temp: %.2f°C\n", temp / 1000.0);
      fclose(fp);
      sleep(1);
   }

   return 0;
}