Search results
Results from the WOW.Com Content Network
The C programming language provides many standard library functions for file input and output.These functions make up the bulk of the C standard library header <stdio.h>. [1] The functionality descends from a "portable I/O package" written by Mike Lesk at Bell Labs in the early 1970s, [2] and officially became part of the Unix operating system in Version 7.
The type-generic macros that correspond to a function that is defined for only real numbers encapsulates a total of 3 different functions: float, double and long double variants of the function. The C++ language includes native support for function overloading and thus does not provide the <tgmath.h> header even as a compatibility feature.
More generally, Python 2.x specifies the built-in file objects as being “implemented using C's stdio package," [48] and frequent reference is made to C standard library behaviors; the available operations (open, read, write, etc.) are expected to have the same behavior as the corresponding C functions (fopen, fread, fwrite, etc.).
Several separate standard headers (for example, stdio.h) specify the interfaces for these and other standard library facilities. Another common set of C library functions are those used by applications specifically targeted for Unix and Unix-like systems, especially functions which provide an interface to the kernel.
For example, an integer can be printed using the "%d" formatting code, e.g.: printf("%d", 42); This formats the integer "42" as text and prints it to the standard output. printf is typically the first function any C programmer encounters, because it is the only function which appears in the standard Hello world program:
C functions are akin to the subroutines of Fortran or the procedures of Pascal. A definition is a special type of declaration. A variable definition sets aside storage and possibly initializes it, a function definition provides its body. An implementation of C providing all of the standard library functions is called a hosted implementation.
In the above example, the main( ) function defines where the program should start executing. The function body consists of a single statement , a call to the printf() function, which stands for " print f ormatted"; it outputs to the console whatever is passed to it as the parameter , in this case the string "hello, world" .
The C programming language manages memory statically, automatically, or dynamically.Static-duration variables are allocated in main memory, usually along with the executable code of the program, and persist for the lifetime of the program; automatic-duration variables are allocated on the stack and come and go as functions are called and return.