Search results
Results from the WOW.Com Content Network
Instead you use this (*ptr).kg and you force compiler to 1st dereference the pointer and enable acess to the chunk of data and 2nd you add an offset (designator) to choose the member. Check this image I made: But if you would have nested members this syntax would become unreadable and therefore -> was introduced.
Jun 8, 2012 at 11:31. printf needs to know the size of the argument in order to print it (to cast it appropriately, so to say). A char has size 1, an int has at least that, on most machines more. Also, when using %c you want a character printed, not a number. In the D language, you would always use %s and let the compiler worry about the types.
Historically, the first extensions used for C++ were .c and .h, exactly like for C. This caused practical problems, especially the .c which didn't allow build systems to easily differentiate C++ and C files. Unix, on which C++ has been developed, has case sensitive file systems. So some used .C for C++ files.
The & operator performs a bit-wise and operation on its integer operands, producing an integer result. Thus (8 & 4) is (0b00001000 bitand 0b00000100) (using a binary notation that does not exist in standard C, for clarity), which results in 0b00000000 or 0. The && operator performs a logical and operation on its boolean operands, producing a ...
pow only works on floating-point numbers (doubles, actually).If you want to take powers of integers, and the base isn't known to be an exponent of 2, you'll have to roll your own.
1. In C, %[^\n] has no meaning. In the scanf formatting language (which is used by C) it means that your code has opened a very large vulnerability to an overflow exploit. Learning the scanf formatting language is not learning C. Indeed, doing so is an impediment to learning C. – William Pursell.
3. The * in declaration means that the variable is a pointer to some other variable / constant. meaning it can hold the address of variable of the type. for example: char *c; means that c can hold the address to some char, while int *b means b can hold the address of some int, the type of the reference is important, since in pointers arithmetic ...
In C99, the C header <math.h> defines nan(), nanf(), and nanl() that return different representations of NaN (as a double, float, and int respectively), and infinity (if avaliable) could be returned by generating one with log(0) or something. There's no standard way to check for them, even in C99.
In C Pi is defined in math.h: #define M_PI 3.14159265358979323846. And that value is the most accurate representation available to a double precision value. Not quite -- in fact a conforming C implementation may not define PI in <math.h>. POSIX specifies M_PI, but again, a conforming C implementation may not define it.
If you think of them as pointers, you'll be using * to get at the values inside of them as explained above, but there is also another, more common way using the [] operator: int a[2]; // array of integers. int i = *a; // the value of the first element of a. int i2 = a[0]; // another way to get the first element.