In early implementations of FORTRAN language, a compiler may choose to use static allocation (i.e., allocation in the static area) for local variables and parameters, effectively arranging for the variables of different invocations to share the same locations, and thereby avoiding any run-time overhead for creation and destruction of stack frames. However, such an implemen- tation changes the meaning of recursive function calls. Provide a simple example and explain how its meaning changes under the “FORTRAN” semantics as stated above, compared with standard semantics found in languages like C, Python, and Java.
In early implementations of FORTRAN language, a compiler may choose to use static
allocation (i.e., allocation in the static area) for local variables and parameters, effectively arranging
for the variables of different invocations to share the same locations, and thereby avoiding
any run-time overhead for creation and destruction of stack frames. However, such an implemen-
tation changes the meaning of recursive function calls.
Provide a simple example and explain how its meaning changes under the “FORTRAN” semantics
as stated above, compared with standard semantics found in languages like C, Python, and Java.
1) Static allocation refers to the process of reserving memory for variables during compile-time. The memory allocation is determined before the program is executed and remains fixed throughout the program's runtime. This means that the size and type of data to be stored in the variable are known at compile-time.
2) In statically allocated memory, variables have fixed addresses that are determined at compile-time. This allocation strategy is commonly used for global variables and local variables with the static keyword in languages like C and C++. It is also used for arrays whose size is known at compile-time.
3) Dynamic allocation refers to the process of allocating memory for variables during runtime, as the program is executing. This allows for the creation of variables whose size and type may not be known until the program is actually running.
4) In dynamically allocated memory, variables are assigned memory addresses during program execution, and their size and characteristics can be changed as needed. Languages like C++ (with new and delete operators), C (with malloc() and free() functions), and Java (with the new keyword) support dynamic allocation.
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