Exercise 2 Solution - nexthour Function

MATLAB Function Implementation

function hhout = chap4_prob2_nexthour(hhin)
%{
To test this function, you can use:
for n=1:14, 
nnext = chap4_prob2_nexthour(n);
fprintf('Input: %d, Output: %d\n',n,nnext); 
end
%}
hhout = mod( (hhin), 12 ) + 1;
end

Function Explanation:

Function Name: chap4_prob2_nexthour
Input: hhin - current hour (integer from 1 to 12)
Output: hhout - next hour on a 12-hour clock
Core Logic: Uses modulo arithmetic to handle the wrap-around from 12 to 1

Mathematical Logic:

The function uses the formula: hhout = mod(hhin, 12) + 1

mod(hhin, 12) returns the remainder when hhin is divided by 12
For hours 1-11: mod(hhin, 12) = hhin, so result is hhin + 1
For hour 12: mod(12, 12) = 0, so result is 0 + 1 = 1
For hours > 12: The modulo operation ensures we stay within the 12-hour cycle

Testing the Function:

% Test the function with hours 1 through 14
for n = 1:14
    nnext = chap4_prob2_nexthour(n);
    fprintf('Input: %d, Output: %d\n', n, nnext); 
end

Expected Output: Hours 1→2, 2→3, ..., 11→12, 12→1, 13→2, 14→3

Alternative Implementations:

% Using if-else statement (more verbose)
function hhout = nexthour_alternative(hhin)
    if hhin == 12
        hhout = 1;
    else
        hhout = hhin + 1;
    end
end

Note: The modulo approach is more elegant and handles edge cases better.

Solution to Exercise 2 - nexthour Function