Page 37 - Applied Numerical Methods Using MATLAB

26 MATLAB USAGE AND COMPUTATIONAL ERRORS
Example 5. A switch-case-end Block

%nm119_5: example of switch-case-end block
point = 85;
switch floor(point/10) %floor(x): integer less than or equal to x
case 9, grade = ’A’
case 8, grade = ’B’
case 7, grade = ’C’
case 6, grade = ’D’
otherwise grade = ’F’
end

2. for index = i 0:increment:i last-end Loop
A for loop makes a block of statements executed repeatedly for a specified
number of times, with its loop index increasing from i_0 to a number not
greater than i_last by a specified step (increment) or by 1 if not specified.
The loop iteration normally ends when the loop index reaches i_last, but it
can be stopped by a break statement inside the for loop. The for loop with a
positive/negative increment will never be iterated if the last value (i_last)of
the index is smaller/greater than the starting value (i_0).

Example 6. A for Loop

%nm119_6: example of for loop
point = [76 85 91 65 87];
for n = 1:length(point)
if point(n) >= 80, pf(n,:) = ’pass’;
elseif point(n) >= 0, pf(n,:) = ’fail’;
else %if point(n)< 0
pf(n,:) = ’????’;
fprintf(’\n\a Something wrong with the data??\n’);
break;
end
end
pf

3. while Loop
A while loop will be iterated as long as its predefined condition is satisfied and
a break statement is not encountered inside the loop.
Example 7. A while Loop

%nm119_7: example of while loop
r=1;
whiler<10
r = input(’\nType radius (or nonpositive number to stop):’);
if r <= 0, break, end %isempty(r)| r <= 0, break, end
v = 4/3*pi*r*r*r;
fprintf(’The volume of a sphere with radius %3.1f = %8.2f\n’,r,v);
end