formatting of prime factorization algorithm - matlab

Question

suppose we have following script for prime factorization
z=input('enter your number : ');
for ii=2:z
s=0;
while z/ii==floor(z/ii) % check if z is divisible by ii
z=z/ii;
s=s+1;
end
if s>0
str = [num2str(ii) '^' num2str(s) ];
disp(str) ;
% If z = 1, no more divisions are necessary,
% thus breaks the loop and quits
if z == 1
break
end
end
end
but output of this code is not formatted well,for instance
>> integer_factorization
enter your number : 30
2^1
3^1
5^1
how can i do so that i got
30=2^1*3^1*5^1?
thanks in advance

Answer 1

This is fairly straightforward: Use fprintf(''); instead to print/display the factors.
z=input('enter your number : ');
ans='' %the final answer string
for ii=2:z
s=0;
while z/ii==floor(z/ii) % check if z is divisible by ii
z=z/ii;
s=s+1;
end
if s>0
str = [num2str(ii) '^' num2str(s) ];
%disp(str) ;
strcat(ans,'*',str); %concats the * str as per requirement.
% If z = 1, no more divisions are necessary,
% thus breaks the loop and quits
if z == 1
break
end
end
end
ans=ans(2:end); % to remove the first *
fprintf(ans); % can even use the disp() function.
So, basically, added a string to append the factors into it and display at the end, outside of the loops.

Answer 2

You can simply create a string and add your numbers to the string and finally print the string. something as follow:
z=input('enter your number : ');
for ii=2:z
s=0;
while z/ii==floor(z/ii) % check if z is divisible by ii
z=z/ii;
s=s+1;
end
if s>0
str = str + [num2str(ii) '^' num2str(s) '*' ];%only update
% If z = 1, no more divisions are necessary,
% thus breaks the loop and quits
if z == 1
break
end
end
str = str(0,str.size -1) %use proper command to remove the last * from your string result
disp(str) ; %display the str at the end in one line
end

Answer 3

Litle modification of your code.
z=input('enter your number : ');
for ii=2:z
s=0;
while z/ii==floor(z/ii) % check if z is divisible by ii
z=z/ii;
s=s+1;
end
if s>0
str += [num2str(ii) '^' num2str(s) ];
% If z = 1, no more divisions are necessary,
% thus breaks the loop and quits
if z == 1
break
else
str+='*';
end
end
end
disp(str);

Answer 4

This could work! Just with a few changes to your code
z=input('enter your number : ');
str=[num2str(z) '='];
first=0;
for ii=2:z
s=0;
while z/ii==floor(z/ii) % check if z is divisible by ii
z=z/ii;
s=s+1;
end
if s>0
if first==0
str=[str num2str(ii) '^' num2str(s)];
first=1;
else
str=[str '*' num2str(ii) '^' num2str(s)];
if z == 1
break
end
end
end
end

Answer 5

first of all thanks everyone for your afford, here is my final solution
z=input('enter your number : ');
string='';
for ii=2:z
s=0;
while z/ii==floor(z/ii) % check if z is divisible by ii
z=z/ii;
s=s+1;
end
if s>0
str =[num2str(ii) '^' num2str(s) ];
string=strcat(string,str);
string= strcat(string,'*');
% If z = 1, no more divisions are necessary,
% thus breaks the loop and quits
if z == 1
break
end
end
end
string=string(1:end-1);% remove last sign of multiplicaiton
fprintf('prime factorization is %s\n',string);
here is several examples
>> integer_factorization
enter your number : 30
prime factorization is 2^1*3^1*5^1
another
>> integer_factorization
enter your number : 35
prime factorization is 5^1*7^1
and last one
>> integer_factorization
enter your number : 100
prime factorization is 2^2*5^2