# Write a program that calculates the length of hypotenuse c for all (!) combinations of legs a and b and do so using a for loop!

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Kat Merzelt on 13 Feb 2020
Answered: Stephen Cobeldick on 14 Feb 2020
Dear all,
I need some help with the following:
Write a program that calculates the length of hypotenuse c for all (!) combinations of legs
a and b (a=(3;5;1;3;2) and b=(1;3;2;7;2)) - and do so using a for loop!
Im a total beginner and i have no idea how to do this for all the possible combinations. Thats what im having right now:
for i=1:5
a(i)= input ('Enter a')
b(i)= input ('Enter b')
end
C=sqrt(a.^2+b.^2)
disp (C)
Can someone help?

Raj on 14 Feb 2020
You already know 'a' and 'b' from your problem statement. Just declare them as vectors directly. No need to enter the values one by one. Use proper indexing to compute 'C' for each value of 'a' and 'b' like this:
a=[3;5;1;3;2]
b=[1;3;2;7;2]
C=zeros(length(a),1); % Pre allocate 'C'
for ii=1:length(a)
C(ii,1)=sqrt(a(ii).^2+b(ii).^2);
end
C

Stephen Cobeldick on 14 Feb 2020
The easiest way to get all combinations is to use two loops:
a = [3;5;1;3;2];
b = [1;3;2;7;2];
for ii = 1:numel(a)
for jj = 1:numel(b)
c = sqrt(a(ii).^2 + b(jj).^2);
fprintf('a=%g b=%g c=%g\n',a(ii),b(jj),c)
end
end