CS 101, Week 1

If you want to learn more check out What refers to a choice of values for variables so that all equations are satisfied?

CS 101 Lecture 1We also discuss several other topics like What is the form of quadratic equation?

•Class Website: gaillinois.edu/cs101

•Grading: 20% HW

            25% Labs

            10% Lecture particDon't forget about the age old question of What is an energy in motion?

            20% Midterms →2

            25% final

•Need: Codelab accountDon't forget about the age old question of What is considered as the number one economic problem?
We also discuss several other topics like rpi iclicker

•Diazza -posts containing solutions marked as privateDon't forget about the age old question of disconfirming messages

•Computing

        Byte (groups of 8)

•Algorithms:

        -Python -you type code in and get response right away

        -depth . area -volume

        -volume of rain/volume per raindrop

                -number of raindrops

•What is a program? -a set of instructions a computer executes to achieve a goal

•What is data? Information stored in a computer

        •Binary data must be interpreted:

                -instruction

                -value (#, character)

                -memory location

•Programs are data!

•Program -a set of instructions executed by a computer to achieve a goal

•Python is a high-level language and interpreted language.

        •high-level

        •low-level

        •compiled language -takes entire code →translates to machine language, for output

        And speed

        •interpreted language

•Elements of Programming:

        -what is a literal?

                •fixed value (noun)

                •represents data that doesn’t change

        -executing a literal 

                                                        3 = literal

        -what is an operator?

                •manipulates data (verb)        * = operator

        -Expression -combines literals and operators (phrase)

                •produces a value

                        Ex: 3+5

        Q: 1+1 * 2

             In python =? = 3

        •Python still uses pemdas (order of OP)!

        -what are some other operators?

                •exponentiation **

                •modulus % ------→ .24% 60=24   72% 60=12

                •modulus = remainder

                •// (floor division) =opposite of mod

                        •5/12=2        6//2=3

                        Ex: 7/3 = 2.33                7//3 = 2        7% 3=1

                •bitwise OR, 1

                •bitwise XOR, ^

                •bitwise AND, &

                •bitwise left shift, <<

                •bitwise right shift, >>

                     -ex: 1^2=3

        -the machine state hasn’t changed

        -programs are complex and we need to remember results

        -what is a variable?

                •name memory locations

                •x=3+5 → x=8 in computer

                      x=5

                •ex: x=17+7*9                What is x?        Ans: 80

                •What value is stored in x?

                        x=17+7*9

                        x=3 → overrides first, x=3

        -What is a statement?

                •changes the state of the computer (sentence)

                •ex: an assignment

        -Programs consist of series of statements:

                •a script is a file containing a series of Python statement

                        x=1        ------→  x=2

                        x=x+1

                •a notebook collects a series of Python statements

                •these are stored in text

        -each instruction is executed in order from top to bottom → together they make a program

 (called a comment)                In [  ]: # calculate        x=10

                                                        y=x**2

                                                        y=y+y

        -primary memory is directly accessible to processor