Loops and Conditional Statements Dr.Abbas Lab 4 1ENG. Ahmad Alaql

For loops To run a command more than once as an index varies, you may use a for loop. % display of numbers for i = 1:9 disp(i) End % 6! fact = 1; for i = 2:6 fact = fact * i; end disp(fact) ENG. Ahmad Alaql2

Ex 1: Write m-file to compute the factorial of any integers ! ENG. Ahmad Alaql3

The Solution : N= input('Enter the number to calculate the factorial: '); fact=1; for i=2:N fact=fact*i; end disp(fact) ENG. Ahmad Alaql4

5 % Calculate the Square of numbers 1 to 5 for i = 1:5 disp([int2str(i) ' squared equals ' int2str(i^2)]) end Note : INT2STR used to convert integer to string.

Summing Series total = 0; for n = 1:6 total = total + 2ˆn; end ENG. Ahmad Alaql6

7 % function function [out] = f(in1) out = in1 * sin(in1 *pi/4); % loop maxN = input('Enter the value of N : '); I(1) = f(1); for N=2:maxN I(N) = I(N-1) + f(N); end disp('Values of I_N') disp(I)

>> maxN = input('Enter the value of N : '); for N=2:maxN X= N * sin (N *pi \ 4) end disp('Values of I_N') disp(X) ENG. Ahmad Alaql8

9 EXERCISE : Calculate the summations

ENG. Ahmad Alagil10 While loop: while (condition) commands... end

Examples x=1; while x<=100 disp(x); x=x+1; end ENG. Ahmad Alaql11

ENG. Ahmad Alagil12 EX : Write out the values of x2 for all positive integer values x such that x3 < x = 1; while x^3 < 2000 disp(x^2) x = x+1; end

n = 10; while n > 0 disp('Hello World') n = n - 1; end ENG. Ahmad Alaql13

ENG. Ahmad Alagil14 IF Statement if (expression) commands... elseif (expression) commands... else commands... end

a=50; if a<10 b=a/2; else b=a/5; end ENG. Ahmad Alaql15

ENG. Ahmad Alagil16 if x >= 0 & x <= 1 f = x; elseif x > 1 & x <= 2 f = 2-x; else f = 0; end

Conditional Statements if logical_expression1 statements1 elseif logical_expression2 statements2 else statements3 end ENG. Ahmad Alaql17

if 2>4 a=5 elseif 2<1 a=6 else a=10 end ENG. Ahmad Alaql18

ENG. Ahmad Alagil19 The MATLAB Command switch clc; n=input('Please input the figure:','s') switch n case ('triangle') n=3; sum=(n-3).*(180) case ('square') n=4; sum=(n-3).*(180) case('pentagon') n=5; sum=(n-3).*(180) case ('hexagon') n=6; sum=(n-3).*(180) end

color = 'rose'; switch lower(color) case {'red', 'light red', 'rose'} disp('color is red') case 'blue' disp('color is blue') case 'white' disp('color is white') otherwise disp('Unknown color.') end ENG. Ahmad Alaql20

x=input('Enter the value of N : ') u=input('Enter the value of s : ') switch u case {'in','inch'} % multiple matches y = 2.54*x; % converts to centimeters disp ([num2str(x) ' ' u ' converted to cm is :' num2str(y)]) % disp is used to print pretty in the command window % in the above a string vector is being printed case {'m','meter'} y = x*100; % converts to centimeters disp ([num2str(x) ' ' u ' converted to cm is :' num2str(y)]) case { 'millimeter','mm'} y = x/10; disp ([num2str(x) ' ' u ' converted to cm is :' num2str(y)]) case {'cm','centimeter'} y = x; disp ([num2str(x) ' ' u ' converted to cm is :' num2str(y)]) otherwise disp (['unknown units:' units]) y = nan; % not a number end ENG. Ahmad Alaql21

ENG. Ahmad Alagil22 HW.3