steenrod% g++ -o quarts-3 quarts-3.cc
steenrod% quarts-3
Enter volume in quarts: 4
4 quarts = 3.78533 liters
steenrod% quarts-3
Enter volume in quarts: -4
Value of quarts must be positive; enter value again: 0
Value of quarts must be positive; enter value again: 2
2 quarts = 1.89267 liters