Stream operators Input friend istream & operator (istream &, T &); Output friend ostream &operator (istream & s, point & p); friend ostream &operator p; cinpp2; cout p.x p.y; return s; } ostream &operator ...
The scope operator as a non-OO C++ extension int fun(); int i; class C { int i; public: void test(); int fun(); }; void C::test() { i++; // C::i++ ::i++; // global i fun(); // C::fun() ::fun(); // global fun() } ...
Variable function argument list in C we write: int printf(char *, …); in C++ a bit simpler: int printf(char * …); // comma not required, but only if // variable preceding ”…” has no default value. // Macros for accessing args in (like in C) ...
A simplified copying program #include #include #define PERMS 0666 /* RW for owner, group, others */ /* cp: copy f1 to f2 */ int main(int argc, char *argv[]) { int f1, f2, n; char buf[BUFSIZ]; if (argc != 3) fprintf(stderr,"Usage: cp from to"); if ((f1 = open(argv[1], O_RDONLY, 0)) == -1...
ANSI C Translation Phases Every trigraph sequence in the source file is replaced Every backslash/new-line character pair is deleted The source is converted into preprocessing tokens and sequences of white spaces Each comment is effectively replaced by a space character Every preprocessing...
Conditional Inclusion The #if line evaluates a constant integer expression If the expression is non-zero, subsequent lines until an #endif or #elif or #else or #elifdef or #elifndef are included The expression defined( name ) in a #if is 1 if the name has been defined, and 0 Otherwise
F unctions in C99 acosh asinh atanh cbrt copysign( x , y ) erf erfc exp2( x ) expm1( x ) fdim( x , y ) inverse hyperbolic cosine inverse hyperbolic sine inverse hyperbolic tangent cube root returns the value of x with the sign of y error function complementary error function rai...
Line buffered input Each line input is stored in a buffer Problems can arise when a program does not process all the data in a line, before it wants to process the next line of input Consider the following code: int x; char st[31]; printf(&qu...
Low Level I/O - Read and Write int n_read = read(int fd, char *buf, int n); int n_written = write(int fd, char *buf, int n); Each call returns a count of the number of bytes transferred On reading, the number of bytes returned may be less than the number requested A return value of zero bytes...
Macro substitu tion A definition has the form #define name replacement_text Subsequent occurrences of the token name will be replaced by the replacement_text The name in a #define has the same form as a variable name The replacement text is arbitrary The replacement text is the rest of th...
