Which type of error it will be, if any function or a pointer tries to make changes to the value of const variable?

Answer 1

It can result in unpredictable behavior by the code

Answer 2

for instance,In C++

const int a=10;
Error:______ of read-only variable 'a'

it can be the type of changes that is done to the constant variable
for example:
error: assignment of read-only variable 'a'
error: increment of read-only variable 'a'