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Languages such as C use stack space for variables, and the collection of variables allocated for a subroutine is known as a stack frame. While the computer will set aside the appropriate amount of space for the stack frame, it usually does so simply by adjusting the value of the stack pointer , and does not set the memory itself to any new ...
The latter list is sometimes called the "initializer list" or "initialization list" (although the term "initializer list" is formally reserved for initialization of class/struct members in C++; see below). A declaration which creates a data object, instead of merely describing its existence, is commonly called a definition.
This is typically accomplished by augmenting an accessor method (or property getter) to check whether a private member, acting as a cache, has already been initialized. If it has, it is returned straight away. If not, a new instance is created, placed into the member variable, and returned to the caller just-in-time for its first use.
In C, statically allocated objects without an explicit initializer are initialized to zero (for arithmetic types) or a null pointer (for pointer types).Implementations of C typically represent zero values and null pointer values using a bit pattern consisting solely of zero-valued bits (despite filling bss with zero is not required by the C standard, all variables in .bss are required to be ...
An undefined variable in the source code of a computer program is a variable that is accessed in the code but has not been declared by that code. [1] In some programming languages, an implicit declaration is provided the first time such a variable is encountered at compile time. In other languages such a usage is considered to be sufficiently ...
In B, all variables must be declared, as one of auto, extrn, or implicitly as function arguments. [1] An external variable is defined outside functions, has a lifetime of the whole program execution, and introduced to function by the mean of extrn declaration. Using the following code in the tutorial as an example: [1]
In computer programming, a static variable is a variable that has been allocated "statically", meaning that its lifetime (or "extent") is the entire run of the program. This is in contrast to shorter-lived automatic variables, whose storage is stack allocated and deallocated on the call stack; and in contrast to dynamically allocated objects, whose storage is allocated and deallocated in heap ...
In C/C++, it is possible to declare the parameter of a function or method as constant. This is a guarantee that this parameter cannot be inadvertently modified after its initialization by the caller. If the parameter is a pre-defined (built-in) type, it is called by value and cannot be modified. If it is a user-defined type, the variable is the ...