Can an array be an
lvalue?
Answer:
In FAQ I.9, 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;
You could, however,
use a for loop to iterate through each element of the array and assign
values individually, such as in this example:
int i;
int x[5];
int y[5];
...
for (i=0; i<5; i++)
x[i] = y[i]
...
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:
typedef struct t_name
{
char last_name[25];
char first_name[15];
char middle_init[2];
} NAME;
...
NAME my_name, your_name;
...
your_name = my_name;
...
In the preceding
example, the entire contents of the my_name structure
were copied into the your_name structure. This is essentially the same as the following line:
memcpy(your_name, my_name,
sizeof(your_name));
Cross Reference:
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Posted By Sundeep aka SunTechie
Sundeep is a Founder of Youth Talent Auzzar, a passionate blogger, a programmer, a developer, CISE and these days he is pursuing his graduation in Engineering with Computer Science dept.
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