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function p = binary_search(A,t)
%% Binary Search
% This function binary searches target value (t) in sorted (in increasing order) array A.
% Binary search compares the target value to the middle element of the
% array. If they are not equal, it determines the half part of array in which the taget might be existed,
% then changes the search range from left or right to half array range and
% repeat searching for this new range.
% If target can be found in array, this function returns its index.
% If target can not be found in array, it displays "target is not found in
array_length = length(A);
counter = 0; % number of iteration in searching algorithm
L_SearchRange = 1; %initial search range
R_SearchRange = array_length;
while counter <= floor(log(array_length))+1 %maximum iteration needed to find the target
mid = (L_SearchRange + R_SearchRange)/2;
if t == A(floor(mid))
p = floor(mid);
else if t > A(floor(mid))
L_SearchRange = floor(mid)+1;
R_SearchRange = floor(mid)-1;
if R_SearchRange == 0 %to stop searching when t is less than the minimum value of array
counter = counter +1;
counter = counter+1;
if counter > floor(log(array_length))+1
disp('target is not found in aray')