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Pointers in Pascal are type safe; i.e. a pointer to one data type can only be assigned to a pointer of the same data type. Also pointers can never be assigned to non-pointer variables. Pointer arithmetic (a common source of programming errors in C, especially when combined with endianness issues and platform-independent type sizes) is not ...
The version termed Pascal-P1 was coined after the fact for the many different sources for Pascal-P that existed. The compiler was redesigned to enhance portability, and issued as Pascal-P2. This code was later enhanced to become Pascal-P3, with an intermediate code backward compatible with Pascal-P2, and Pascal-P4, which was not backward ...
An autorelative pointer is a pointer whose value is interpreted as an offset from the address of the pointer itself; thus, if a data structure has an autorelative pointer member that points to some portion of the data structure itself, then the data structure may be relocated in memory without having to update the value of the auto relative ...
This is an accepted version of this page This is the latest accepted revision, reviewed on 29 January 2025. Language for communicating instructions to a machine The source code for a computer program in C. The gray lines are comments that explain the program to humans. When compiled and run, it will give the output "Hello, world!". A programming language is a system of notation for writing ...
Where "new" is the standard routine in Pascal for allocating memory for a pointer, and "hex" is presumably a routine to print the hexadecimal string describing the value of an integer. This would allow the display of the address of a pointer, something which is not normally permitted. (Pointers cannot be read or written, only assigned.)
One of the most notable uses of P-Code machines is the P-Machine of the Pascal-P system. The developers of the UCSD Pascal implementation within this system construed the P in P-code to mean pseudo more often than portable; they adopted a unique label for pseudo-code meaning instructions for a pseudo-machine.
In languages with typed pointers like C, the increment operator steps the pointer to the next item of that type -- increasing the value of the pointer by the size of that type. When a pointer (of the right type) points to any item in an array, incrementing (or decrementing) makes the pointer point to the "next" (or "previous") item of that array.
In C++, classes can be forward-declared if you only need to use the pointer-to-that-class type (since all object pointers are the same size, and this is what the compiler cares about). This is especially useful inside class definitions, e.g. if a class contains a member that is a pointer (or a reference) to another class.