// test: echo -e 'mem\nmem (3)\nsto (4, pi)' | calc.exe | grep -q "error out of bound"
// test: echo -e 'mem (-1)' | calc.exe | grep -q "error"
// test: echo -e 'sto (2, 3)\nmem (2)\ndisp' | calc.exe | grep -q 'storage: 0 3$'
// test: echo -e 'mem\nmem (3)\nsto (4, pi)' | calc.exe | grep -q "error out of bound"
// test: echo -e 'mem (-1)' | calc.exe | grep -q "error"
// test: echo -e 'sto (2, 3)\nmem (2)\ndisp' | calc.exe | grep -q 'storage: 0 3$'