C++ :: Completely Random Distribution Of Numbers

I'm looking to code a completely random distribution of numbers that doesn't affect performance using rand. I believe this code would be ideal but I don't understand how to use it. Where would I input the range of numbers and the quantity?

double uniform_deviate ( int seed ){
return seed * ( 1.0 / ( RAND_MAX + 1.0 ) );
} int r = M + uniform_deviate ( rand() ) * ( N - M );

And for the seed...

unsigned time_seed(){
time_t now = time ( 0 );
unsigned char *p = (unsigned char *)&now;
unsigned seed = 0;
size_t i;
for ( i = 0; i < sizeof now; i++ )
seed = seed * ( UCHAR_MAX + 2U ) + p[i];
return seed;
} srand ( time_seed() );