关于matlab,调试的时候出现Error:The expression to the left of the equals sign is not a valid……

题目

关于matlab,调试的时候出现Error:The expression to the left of the equals sign is not a valid……
please input test score:a=input('please input test score,0 means out:')
while =0
switch =0
case a>100|a=90
disp('the grade is ''A''')
case a>=80
disp('the grade is ''B''')
case a>=70
disp('the grade is ''C''')
case a>=60
disp('the grade is ''D''')
otherwise
disp('the grade is ''E''')
end
a=input('please input test score:')
end
调试的时候出现
Error:The expression to the left of the equals sign is not a valid target for an assignment.

答案

%please input test score:% 这句是注释
a=input('please input test score,0 means out:')
while =0
switch =0
case a>100|a=90
disp('the grade is ''A''')
case a>=80
disp('the grade is ''B''')
case a>=70
disp('the grade is ''C''')
case a>=60
disp('the grade is ''D''')
otherwise
disp('the grade is ''E''')
end
a=input('please input test score:')
end