Explanation : In computing, 'real number' often refers to non-complex floating-point numbers. It include both rational numbers, such as 42 and 3/4, and irrational numbers such as pi = 3.14159265...
When the accuracy of the floating point number is insufficient, we can use the double to define the number. The double is same as float but with longer precision and takes double space (8 bytes) than float.
To extend the precision further we can use long double which occupies 10 bytes of memory space.
In C, you should include stdlib.h. This will give you the function prototypes for the family of malloc functions (malloc, calloc, realloc, and free). Some compiler vendors provide access to these functions through other header files as well, but stdlib.h is the most portable one to use.
Explanation : strstr is a C standard library string function as defined in string.h. strstr() has the function signature char * strstr(const char *haystack, const char *needle); which returns a pointer to a character at the first index where needle is in haystack, or NULL if not present.
Explanation : Yes, you can have multiple declarations (or prototypes), but you can only have one function definition for a given function name in C, or function name + arguments in C++. This needs to be supported for the very frequent situation where a function has prototypes in several include files but only one definition.
Explanation : True, Depending on the operating system/compiler/system architecture you are working on, the range of data types can vary.
Explanation : No, Two different operators may have same associativity.
Explanation : Yes, you can use float as a return type in C. Yes you can use, write prototype before calling that function otherwise compiler will assume it has a int and returns the int value.
Explanation : A preprocessor directive is a message from compiler to a linker. When the preprocessor encounters #define directive, it replaces any occurrence of symbol in the rest of the code by replacement
Explanation : In case, if we don't have address to be assigned to a pointer, then we can simply use NULL. NULL vs Uninitialized pointer – An uninitialized pointer stores an undefined value. A null pointer stores a defined value, but one that is defined by the environment to not be a valid address for any member or object.
Explanation : Structure can contain a Pointer to itself. Such structures are called self-referential structures.
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