My Xterm launcher script

runXterm.cc

#include <vector>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <unistd.h>
#include <cstdio>

using namespace std;

/* saturation, value and hue all are 0..1 */
static void MakeTint(char *dest, double saturation, double value, double hue)
{
    const double v = value * 255.0;
    hue *= 6.0;
    const double f = hue - (int)hue;
    const double x = v * (1.0 - saturation);
    const double y = v * (1.0 - (saturation * f));
    const double z = v * (1.0 - (saturation * (1.0 - f)));
    
    unsigned hex;
     
    switch((int)hue)
    {
        case 0: hex = (((unsigned)v) << 16) | (((unsigned)z) << 8) | ((unsigned)x); break;
        case 1: hex = (((unsigned)y) << 16) | (((unsigned)v) << 8) | ((unsigned)x); break;
        case 2: hex = (((unsigned)x) << 16) | (((unsigned)v) << 8) | ((unsigned)z); break;
        case 3: hex = (((unsigned)x) << 16) | (((unsigned)y) << 8) | ((unsigned)v); break;
        case 4: hex = (((unsigned)z) << 16) | (((unsigned)x) << 8) | ((unsigned)v); break;
        default:hex = (((unsigned)v) << 16) | (((unsigned)x) << 8) | ((unsigned)y); break;
    }
    
    sprintf(dest, "#%06X", hex);
}


int main(int argc, char** argv)
{
    srand48(time(NULL));
    
    double tint = drand48();
    
    static char Tausta[8]  = "#000000";
    static char Kursori[8] = "#FFFFFF";
    MakeTint(Tausta,  0.15, 1.00, tint);
    MakeTint(Kursori, 0.20, 1.00, tint);
    
    static const char *const parms[] =
    {
        "xterm",
        "-bg", "black",
        "-fg", "gray",
        "-fn", "-misc-fixed-bold-r-normal--15-140-75-75-c-90-iso10646-1",
        "-fb", "-misc-fixed-bold-r-normal--15-140-75-75-c-90-iso10646-1",
        "-en", "UTF-8", "-u8",
        "+rv",
        "+bdc",
        "-T", "Uterm", 
        "-wc",
        "-bw", "0",
        "-cr", Kursori,
        "-k8",
        "-sl", "5000",
        "-geometry", "132x50"
    };
    
    std::vector<const char*> p;
    p.assign(parms, parms + sizeof(parms)/sizeof(*parms));
    p.insert(p.end(), argv+1, argv+argc);
    p.push_back(NULL);
    putenv( (char *) "LC_ALL=en_US");
    execvp(parms[0], (char* const*) &p[0]);
    return 0;
}