An lvalue was defined as an expression to which a value can be assigned. Is an array an expression
to which we can assign a value? The answer to this question is no, because an array is composed of several separate array elements that cannot be treated as a whole for assignment purposes.
The following statement is therefore illegal:
int x[5], y[5];
x = y;
Additionally, you might want to copy the whole array all at once. You can do so using a library function such as the memcpy() function, which is shown here:
memcpy(x, y, sizeof(y));
It should be noted here that unlike arrays, structures can be treated as lvalues. Thus, you can assign one
structure variable to another structure variable of the same type, such as this:
Basically lvalue is a storage location where data can be stored/ assigned and moreover it is not an expression. rvalue is an expresion which has a value. all lvalues can be used as rvalues. But all rvalues can't be used as lvalues. int a[100];a is always an rvalue, but a[i] can be lvalue as well as rvalue
The rvalue is the data value of the variable, that is, what information it contains. The "r" in rvalue can be thought of as "read" value. A variable also has an associated lvalue. The "l" in lvalue can be though of as location, meaning that a variable has a location that data or information can be put into. This is contrasted with a constant. A constant has some data value, that is an rvalue. But, it cannot be written to. It does not have an lvalue.
