%% Problem 1

clear;clc;

s = input('Enter the size of the square')


while s <= 0 | s > 26
    disp('The size must be between 1 and 26')
    s = input('Try again: enter the size of the square')
end

a = input('Enter a single character used for the background', 's')
Vec1 = double(a);

while length(Vec1) > 1
        disp('Enter only a single printable character!')
        a = input('Enter the background character again', 's')
        Vec1 = double(a)
end

MTX(s,s) = 0

for i = 1:s
    for j = 1:s
       if i == j
            MTX(i,j) = double('A') - j + s
       elseif i > j
           MTX(i,j) = a
       end
    end
end

char(MTX)