matlab编程实现：一个数向上取整至最高位

以下是一个MATLAB函数，可将输入的数字向上取整至最高位：

function [roundedNum] = ceilToHighestDigit(num)
% This function takes in a number and rounds it up to the highest digit.

% Convert the number to a string
numStr = num2str(num);

% Get the length of the string
numLen = length(numStr);

% Extract the first digit
firstDigit = str2double(numStr(1));

% If the number is a single digit, return it
if numLen == 1
    roundedNum = firstDigit;
    return;
end

% If the first digit is 9, add a new digit and set it to 1
if firstDigit == 9
    roundedNum = str2double(['1' zeros(1,numLen-1)]);
else
    % Otherwise, increment the first digit and set all other digits to 0
    roundedNum = str2double([numStr(1)+1 zeros(1,numLen-1)]);
end

使用示例：

>> ceilToHighestDigit(123)
ans =
   1000
>> ceilToHighestDigit(9)
ans =
     10
>> ceilToHighestDigit(999)
ans =
  1000