Code

 Header...
void skipline (void);

 int main(){
   ... 

»  int x, y;

»  while (1==1) {
»    printf("Please enter two integers > 0\n");

»    if (scanf("%d %d", &x, &y)!=2) 
      skipline();
    else if (x<=0||y<=0) 
      printf("Only integers greater than zero are allowed\n");
    else 
      break;

»    printf("\n\tPlease try again.\n\n");
  }
    
»  printf("Read: %d %d\n", x, y);
»  return 0;
}

//
// Read and discard the rest of the line from stdin, printing it so
// the user knows what's going on. 
//
 void skipline(void){
   ... 

»  int i;
  
»  printf("\nSkipping unexpected input: ");

»  while ((i=getc(stdin))!='\n') {
»    if (i==EOF) {
»      printf("End of standard input\n");
»      exit(1);
}
»    putc(i, stdout);
  }

»  putc('\n', stdout);
}