Obtains a random integer value #include <stdlib.h> int rand( void ); The rand( ) function returns a pseudorandom number between 0 and RAND_MAX. The symbolic constant RAND_MAX is defined in stdlib.h, and is equal to at least 32,767 (or 215 -1). To initialize the pseud-random number generator, call the srand( ) function with a new seed value before the first call to rand( ). This step ensures that rand( ) provides a different sequence of random numbers each time the program runs. If you call rand( ) without having called srand( ), the result is the same as if you had called srand( ) with the argument value 1. Exampleprintf( "Think of a number between one and twenty.\n" "Press Enter when you're ready." ); getchar( ); srand( (unsigned)time( NULL ) ); for ( int i = 0; i < 3; i++ ) // We get three guesses. { printf( "Is it %u? (y or n) ", 1 + rand( ) % 20 ); if ( tolower( getchar( ) ) == 'y' ) { printf( "Ha! I knew it!\n" ); exit( 0 ); } getchar( ); // Dicard newline character. } printf( "I give up.\n" ); |