SUNY Geneseo Department of Computer Science

Expressions, Day 1

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Misc

Quiz

“License” error: Only 30 people can use Matlab concurrently at Geneseo, error on launch means you’re the 31st.

TA office hours

• Samir: Sunday, 6 - 8 PM, South 341A
• Nick: Tuesday, 6 - 8 PM, South 341A

Handout for today & Monday / Wednesday lesson

Questions?

± for quadratic equation?

• Write 2 separate expressions

Or (||) vs exclusive or (exor)?

• p || q, exor(p,q) roughly equivalent to English “p or q”
• Except if p true and q true, in which case…
  • p || q is true
  • But exor(p,q) is false

Quiz Solution

Question 1

• x = 2 ^ 3 / 4 means set x equal to 2³ ÷ 4, i.e., 8 ÷ 4, i.e., 2
• y = 1 + 3 * 2 means set y equal to 1 + 3 × 2, i.e., 1 + 6, i.e., 7
• x = y means set x equal to the value of y, so x ends up equal to 7 (and y is still equal to 7 too)

Question 2

• x == 0 compares x to 0, i.e., asks the question “is x equal to 0”?
• x = 0 sets x equal to 0, i.e., changes the value of x
• 0 = x is an error (assignments must have a variable on the left side of the =)
• 0 ~= x asks the question “is x not equal to 0”?