The basic way to allocate memory for your computer program in C (and C++) is by using malloc()
. malloc()
designates a block of the computer system's memory for your program's use. Once your program is using a segment of memory, no other program can use or access that segment of memory. An attempt to access a segment of memory not allocated to your program will generate a "segmentation fault", and represents an illegal operation on most systems.
Let's look at an example code that allocates a pointer variable i
, then assigns memory to it using malloc()
. We allocate a single integer behind an int*
pointer. After allocation, we store a value inside int
, using the dereferencing operator *
:
// CREATING AND ALLOCATING MEMORY FOR AN INT VARIABLE i int* i; // Declare a pointer variable i i = ( int* )malloc( sizeof( int ) ); // Allocates system memory *i = 0; // Assign the value 0 into variable i printf( "i contains %d", *i ); // Use the variable...