#include <stdio.h>
#include <string.h>

int main(int argc, char** argv)
{
  char buffer[255];
  memset(buffer, '\0', 255);

  int val = 0;
  int a;

  while (1) {
    printf(">>> ");
    fgets(buffer, 255, stdin);

    switch (buffer[0]) {
    case 'q':
      printf("Goodbye!\n");
      return 0;

    case 's':
      sscanf(buffer, "s %d\n", &val);
      printf("Current value: %d\n", val);
      break;

    case 'g':
      printf("Current value: %d\n", val);
      break;

    case 'a':
      sscanf(buffer, "a %d\n", &a);
      val = val + a;
      break;

    default:
      printf("ECHO: %s\n", buffer);
    }
  }
  
  return 0;
}