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To propagate the language rapidly, a compiler porting kit was created in Zürich that included a compiler that generated so called p-code for a virtual stack machine, i.e., code that lends itself to reasonably efficient interpretation, along with an interpreter for that code – the Pascal-P system. The P-system compilers were named Pascal-P1 ...
The original Pascal definition appeared in 1969 and a first compiler in 1970. The first version of C appeared in 1972. Both are descendants of the ALGOL language series. ALGOL introduced programming language support for structured programming, where programs are constructed of single entry and single exit constructs such as if, while, for and case.
Because indirection is a fundamental aspect of algorithms, pointers are often expressed as a fundamental data type in programming languages; in statically (or strongly) typed programming languages, the type of a pointer determines the type of the datum to which the pointer points.
In C and C++, constructs such as pointer type conversion and union — C++ adds reference type conversion and reinterpret_cast to this list — are provided in order to permit many kinds of type punning, although some kinds are not actually supported by the standard language. In the Pascal programming language, the use of records with variants ...
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 Pascal and other Wirth programming languages, it is a general rule that all entities must be declared before use, and thus forward declaration is necessary for mutual recursion, for instance. In C, the same general rule applies, but with an exception for undeclared functions and incomplete types.
See Unit type#In programming languages for a comparison. C and C++ also support the pointer to void type (specified as void *), but this is an unrelated notion. Variables of this type are pointers to data of an unspecified type, so in this context (but not the others) void * acts roughly like a universal or top type.
Ada is a structured, statically typed, imperative, and object-oriented high-level programming language, inspired by Pascal and other languages. It has built-in language support for design by contract (DbC), extremely strong typing , explicit concurrency, tasks, synchronous message passing, protected objects, and non-determinism .