student

cau3 M-files

2 M-files 2.1 Script M_Files Trong Matlab, yeu cau cua chung ta d­oc thuc hien tai dau nhac cua Matlab trong cua so lenh la nhanh va hieu qua. Tuy nhien vi so lenh tang len, hoac khi ban muon thay doi gia tri cua mot hoac nhieu bien va thuc hien lai mot so lenh voi gia tri moi, neu cu danh lap lai tai dau nhac cua Matlab thi se tro len buon te, do vay Matlab cung cap mot giai phap cho van de nay la: no cho phep ban thay the cac lenh cua Matlab bang mot file van ban don gian va yeu cau mo file va thuc hien chinh xac nhung gi da danh tai dau nhac cua Matlab tai cua so lenh, nhung file nay goi la script file, hoac don gian la M_file. Danh tu "script" de chi rang thuc te Matlab doc tu file kich ban tim thay trong file. Danh tu 'M_ file" de chi rang ten script file do phai ket thuc bang phan mo rong la ".m" nh­ vi du example1.m. De tao mot scrip M_file, chon New trong bang chon file va chon M_file. Thu tuc nay se tao ra man hinh soan thao, va ta co the danh d­oc cac lenh cua Matlab vao trong do.

Vi du sau cho ta biet d­oc dien tich hinh chu nhat function example1 dai=4; rong=5; dientich = dai*rong Ta co the ghi va l­u tru file nay bang cach chon Save tu bang chon file hoac an to hop phim tat Ctrn + S. Khi ghi ten file phai chu y danh ten file trung voi ten ham (example1) khong can danh vao phan mo rong, Matlab tu gan cho no. Khi do tu dau nhac ta co the danh: >> example1

dientich =

20 D­oi day la mot so lenh he thong t­ong tac voi *.mfile th­ong gap.

Ten lenh Chuc nang disp(ans) Hien thi cac ket qua ma khong hien ten bien. type Lenh cho xem noi dung file, ngam dinh file o dang M-file. what Lenh nay cho biet tat ca cac files M-files va MAT-file co trong vung lam viec hien hanh hay khong. input Su dung dau nhac de d­a du lieu vao. pause Dung lai cho den khi ng­oi dung nhan mot phim bat ky. pause(n) Dung lai n giay. Waitforbuttonpress Dung lai cho den khi ng­oi dung nhan chuot hoac phim.

Vi du ve ham disp, input function example2 chieu_dai=input('chieu dai hinh chu nhat:'); chieu_rong=input('chieu rong hinh chu nhat:'); dien_tich=chieu_dai*chieu_rong; disp('Dien tich la:') disp(dien_tich) Ket qua khi xuat trinh la: >> example2 chieu dai hinh chu nhat:4 chieu rong hinh chu nhat:5 Dien tich la: 20 Vi du ve ham type

>> type example2

function example2 chieu_dai=input('chieu dai hinh chu nhat:'); chieu_rong=input('chieu rong hinh chu nhat:'); dien_tich=chieu_dai*chieu_rong; disp('Dien tich la:') disp(dien_tich)

Vi du: tinh dien tich hinh tam giac