tap hop lenh duoc chay theo thu tu.
ban luyen
Crystal
lo trinh thuc hanh de hoc Crystal tu con so 0
dinh nghia truoc
Crystal la gi
Crystal dung de viet chi dan chinh xac. O day ban hoc theo lo trinh thuc hanh de hoc Crystal tu con so 0. Hay bat dau voi mot mo hinh: dau vao qua cac buoc roi thanh dau ra.
thong tin chay toi thieutep
app.crchay crystal run app.crthoi quen hoc mot phan nho cua Crystal, go vi du toi thieu roi chaygia tri la du lieu. bien la ten de giu du lieu.
mot viec nho co ten, nhan dau vao va tao ket qua.
Crystal compiler chay code trong app.cr.
doan code dau tien
dau ra chuong trinh
entry point output syntax putsputs 42
dau ra 42pha he ngon ngu
cay pha he Crystal
xem Crystal den tu dau, gan voi ngon ngu nao, va nen hoc gi tiep.
tu con so 0
1doc mot quy tac2doan dau ra3go bang tri nho4chay kiem tra5lap lai voi mot thay doi
Ngan hang cau hoi
Tim truoc khi luyen
Chon giai doan hoac tim trong ngan hang cua ngon ngu nay roi mo bai tap.
Q 1Lua chonGiai doan 1 dinh nghia
Crystal cau 1
Crystal cau 1. Chon mo ta phu hop nhat voi in mot gia tri.
Q 2Lua chonGiai doan 1 dinh nghia
Crystal cau 2
Crystal cau 2. Chon mo ta phu hop nhat voi dat ten cho gia tri.
Q 3Lua chonGiai doan 1 dinh nghia
Crystal cau 3
Crystal cau 3. Chon mo ta phu hop nhat voi ham tai su dung.
Q 4Lua chonGiai doan 1 dinh nghia
Crystal cau 4
Crystal cau 4. Chon mo ta phu hop nhat voi tap hop co ban.
Q 5Lua chonGiai doan 1 dinh nghia
Crystal cau 5
Crystal cau 5. Chon mo ta phu hop nhat voi in mot gia tri.
Q 6Lua chonGiai doan 1 dinh nghia
Crystal cau 6
Crystal cau 6. Chon mo ta phu hop nhat voi dat ten cho gia tri.
Q 7Lua chonGiai doan 1 dinh nghia
Crystal cau 7
Crystal cau 7. Chon mo ta phu hop nhat voi ham tai su dung.
Q 8Lua chonGiai doan 1 dinh nghia
Crystal cau 8
Crystal cau 8. Chon mo ta phu hop nhat voi tap hop co ban.
Q 9Lua chonGiai doan 1 dinh nghia
Crystal cau 9
Crystal cau 9. Chon mo ta phu hop nhat voi in mot gia tri.
Q 10Lua chonGiai doan 1 dinh nghia
Crystal cau 10
Crystal cau 10. Chon mo ta phu hop nhat voi dat ten cho gia tri.
Q 11Lua chonGiai doan 1 dinh nghia
Crystal cau 11
Crystal cau 11. Chon mo ta phu hop nhat voi ham tai su dung.
Q 12Lua chonGiai doan 1 dinh nghia
Crystal cau 12
Crystal cau 12. Chon mo ta phu hop nhat voi tap hop co ban.
Q 13Lua chonGiai doan 1 dinh nghia
Crystal cau 13
Crystal cau 13. Chon mo ta phu hop nhat voi in mot gia tri.
Q 14Lua chonGiai doan 1 dinh nghia
Crystal cau 14
Crystal cau 14. Chon mo ta phu hop nhat voi dat ten cho gia tri.
Q 15Lua chonGiai doan 1 dinh nghia
Crystal cau 15
Crystal cau 15. Chon mo ta phu hop nhat voi ham tai su dung.
Q 16Lua chonGiai doan 1 dinh nghia
Crystal cau 16
Crystal cau 16. Chon mo ta phu hop nhat voi tap hop co ban.
Q 17Lua chonGiai doan 1 dinh nghia
Crystal cau 17
Crystal cau 17. Chon mo ta phu hop nhat voi in mot gia tri.
Q 18Lua chonGiai doan 1 dinh nghia
Crystal cau 18
Crystal cau 18. Chon mo ta phu hop nhat voi dat ten cho gia tri.
trac nghiem
Crystal cau 1
Crystal cau 1. Chon mo ta phu hop nhat voi in mot gia tri.
puts 42
tham khao
mau cho app.cr
Crystal compiler
crystal run app.crentry point output syntax puts
dau ra chuong trinh
puts 42
- Run the smallest file first
- Print one known value
- Check the output before adding more code
variables assignment types =
gia tri va ten
total = 42 puts total
- Give values readable names
- Keep one idea per line while learning
- Trace the value before changing it
function collection Array
ham va tap hop
def add(a : Int32, b : Int32) : Int32 a + b end scores = [40, 2] puts scores.size
- Keep functions small
- Return useful values
- Use the common collection before reaching for frameworks