Macros and strings Formal parameters are not replaced within quoted strings: #define M(iks) printf("iks=%d", iks); int v2=789; M(v2) /* the result: iks=789 */ If a parameter name is preceded by a # in the replacement text, the combina...
Other functions fabs(x) absolute value, |x| ldexp(x,n) x*2 n frexp(x, int *ip) splits x into a normalized fraction in the interval [1/2,1) which is returned, and a power of 2, which is stored in *ip . If x is zero, both parts of the result are zero. modf(x, double *ip) splits x into integra...
Predefined macros variable argument lists Header file: Macros: void va_start(va_list ap, lastfix); type va_arg(va_list ap, type); void va_end(va_list ap); Type: va_list Purpose - to provide a way for defining functions of unknown number of parameters Idea - the function gets a
Random numbers Generating true random numbers is a problem! Usually computers use special functions, generating pseudo random numbers The library stores information to be used in the next call to the generator int rand(void); Returns successive pseudo-random numbers in the range from 0 to R...
SetPixel The SetPixel function sets the pixel at the specified coordinates to the specified color. COLORREF SetPixel( HDC hdc , /* handle to device context */ int X , /* x-coordinate of pixel */ int Y , /* y-coordinate of pixel */ COLORREF crColor /* pixel color */ ); Parameters hdc - Handle ...
Solution Simple method: read and dump all the characters from the input buffer until a '\n' after the scanf() call: void dump_line( FILE * fp ) { int ch; while( (ch = fgetc(fp)) != EOF && ch != '\n' ) /* null body */ ; } Modified code int x; char st[31];
Speed - examp les Intel Celeron M 540 (1862MHz) 0.94 GFLOPs Intel Pentium 4 (3055MHz) 0.73 GFLOPs Intel Core 2 Duo E6300 (1870MHz) 1.8 GFLOPs Intel Core 2 Duo E6600 (3700MHz) 3.4 GFLOPs ...
The function time time_t time(time_t *timer); time gives the current time, in seconds, elapsed since 00:00:00 GMT, January 1, 1970 It stores that value in the location *timer, provided that timer is not a null pointer #include #include int m...
The Year 2038 Bug Tuesday, January 19, 2038, GMT 03:14:07 The counter will overflow and go to negative numbers Proposed solution: use 64-bits numbers - moves the problem to Sunday, December 4 th , year 292 277 026 596 - would be a total solut...
Trigraph sequences The characters in C source: 7-bit ASCII Some character sets don 't cover ASCII For reduced sets: trigraph sequences Replaced by the corresponding single character Replacement occurs before any other processing ??= # ??( [ ?? } ??' ^ ??! | ??- ~ Replacement occurs befo...
