Matlab code for computing large exponentials of the form n^m (n and m integers). Uses chars to store digits, for performance. Handles huge numbers, e.g. 2^1000. Returns the result as a string.

strnpowm.m

function str = strnpowm(base,exponent)
% Computes base^exponent (both integers) and returns the result as a string
% Handles huge numbers, e.g. 2^1000
str = char(1);

for i = 1:exponent
    l = length(str);
    
    product = repmat('0',1,l);
    carry = 0;
    
    for j = l:-1:1
        % Multiply digit by base and add carry
        temp = str(j)*base + carry;

        % Compute carry
        carry = floor(t/10);
        
        % Store least significant digit of temp
        product(j) = temp - carry*10;
    end
    
    % Prepend carry if there is a nonzero carry.
    if carry > 0
        str = [carry, product];
    else
        str = product;
    end
end

% Convert to human readable integer characters
str = char(str+48);

end