What is this mean when it shows in the errors?

Question

1)
Expression must be a modifiable lvalue
2)
'=' left operand must be l-value

Answer 1

there are two different types l and r... lvalue means left side of operation... this should be variable and not constant...rvalue should be constant

int a;
2= a; // lvalue err

it's error as we are trying to assign something to constant value 2