title: Triangular Numbers
signature: function triangular_numbers(num)
test_code: using Printf
  
  # SOLUTION CODE
  # ============================================
  PLACEHOLDER_CODE_BODY
  
  # TESTING CODE 
  # ============================================
  function validate_solution(actual, expected)
      return actual == expected
  end
  
  function driver(num, expected)
      try
  
          if validate_solution(PLACEHOLDER_FN_NAME(num), expected)
              return "PASSED";
          end
          return "FAILED";
      catch exception_obj
          return string(Base.typename(typeof(exception_obj)).wrapper);
      end
  end
  
  function main()
      
      result = driver(97, false);
      @printf("TEST-0...%s\n",result);
      
      result = driver(97, false);
      @printf("TEST-1...%s\n",result);
      
      result = driver(32, false);
      @printf("TEST-2...%s\n",result);
      
      result = driver(40, false);
      @printf("TEST-3...%s\n",result);
      
      result = driver(18, false);
      @printf("TEST-4...%s\n",result);
      
      result = driver(14, false);
      @printf("TEST-5...%s\n",result);
      
      result = driver(90, false);
      @printf("TEST-6...%s\n",result);
      
      result = driver(39, false);
      @printf("TEST-7...%s\n",result);
      
      result = driver(1, true);
      @printf("TEST-8...%s\n",result);
      
      result = driver(57, false);
      @printf("TEST-9...%s\n",result);
      
  end
  
  main()
source_py: def triangular_numbers(num):
      if (num < 0):
          return False
      (sum, n) = (0, 1)
      while (sum <= num):
          sum = (sum + n)
          if (sum == num):
              return True
          n += 1
      return False
source_cpp: bool triangular_numbers(int num) {
    if ( num < 0 ) return false;
    int sum = 0;
    for ( int n = 1;
    sum <= num;
    n ++ ) {
      sum = sum + n;
      if ( sum == num ) return true;
    }
    return false;
  }