Automatic variable
From Wikipedia, the free encyclopedia
Automatic variables are variables local to a block. They are automatically allocated on the stack when that block of code is entered. When the block exits, the variables are automatically deallocated.
for example, try the following code:
main()
{
{
int a;
a = 10;
}
{
int b;
printf("b = %d\n", b);
}
}
Using the gcc compiler this will give the output
b = 10
because the same memory location that was allocated to a is allocated to b when the second block is entered.
Automatic variables will have an undefined value when declared, so it is good practice to initialize it with valid value before using it.
