Week 1-Start with DrRocket

My computer studies started with a short introduction of computer history and a programming language-DrRocket. DrRocket is designed for different people regards to their experiences with computer language, and it has language for beginning student, intermediate student and advanced student. As a student who is not really familiar with programming, I am using intermediate student with lambda.

To deal with pictures, (require picturing-programs) should always be written in the first line. Below are many functions that can be used in terms of manipulating images:

(flip-vertical im)

(flip-horizontal im)

(rotate 180 im)

(rotate-cw im)

(rotate-ccw im)

(scale 3 im)

(scale/xy 3 1/3  im)

(image-width im)

(image-height im)

(crop-top im 100)

(crop-left im 100 )

(beside im1 im2)

(above im1 im2)

(overlay im1 im2)

I also learned about how to build a image: (circle size “solid” “color”)

In addition, there are other functions that related with numbers and strings:

(quotation 5 3)

(reminder 5 3)

(+ ½ ¾ 1 4 7)

(/ 1 6 3/5 3 6)

(round e)

(floor e)

(inexact->exact #i3.0)

(numerator -2.55)

(denominator -2.55)

(string-length “2245778”)

(string-append “all” “together”)

(substring “123567” 3 6)