The problem is that you are not storing the answers/toss.
A=input('How many tossing would you like to do? ')
x= rand(A,1);
toss = nan(A,1);
for i=1:length(x)
if x(i)<0.5
toss(i) = -1; %Head
elseif x(i)>=0.5
toss(i) = 1; %Tail
else
disp('Error...')
end
end
histogram(toss)
Edit: If you want it more neat
A=input('How many tossing would you like to do? ')
x= rand(A,1);
above = x < 0.5;
x(above)=-1;
x(~above)=1;
histogram(toss)
