fly.c

/*C program to design flying characters Screen Saver.*/

#include <stdio.h>

#include <termios.h>

#include <unistd.h>

#include <fcntl.h>

/*will return character based on passed number*/

char getCHAR(int n)

{

    char ok[] = "~!@#$%^&*:;'\",{}|<>=";

    return ok[n];

}

/*function to identify that any key hit by the keyboard*/

int kbhit(void)

{

    struct termios oldt, newt;

    int ch;

    int oldf;

    tcgetattr(STDIN_FILENO, &oldt);

    newt = oldt;

    newt.c_lflag &= ~(ICANON | ECHO);

    tcsetattr(STDIN_FILENO, TCSANOW, &newt);

    oldf = fcntl(STDIN_FILENO, F_GETFL, 0);

    fcntl(STDIN_FILENO, F_SETFL, oldf | O_NONBLOCK);

    ch = getchar();

    tcsetattr(STDIN_FILENO, TCSANOW, &oldt);

    fcntl(STDIN_FILENO, F_SETFL, oldf);

    if (ch != EOF) {

        ungetc(ch, stdin);

        return 1;

    }

    return 0;

}

/*move cursor on specified position on screen*/

void gotoxy(int x, int y)

{

    printf("%c[%d;%df", 0x1B, y, x);

}

int main(void)

{

    int x, y;

    long int i, j;

    i = j = 0;

    x = 1;

    y = 20;

    system("clear");

    /*program will run until any key hit*/

    while (!kbhit()) {

        x = rand() % ((150 - 1 + 1) + 1);

        y = rand() % ((50 - 1 + 1) + 1);

        gotoxy(x, y);

        printf("%c", getCHAR(rand() % ((20 - 1 + 1) + 1)));

        fflush(stdout);

        ++i;

        if (i == 10000) {

            ++j;

            i = 0;

        }

        if (j == 100000) {

            i = 0;

        }

        if (j <= 100)

            usleep(30000);

        if (j <= 1000)

            usleep(3000);

        if (j <= 10000)

            usleep(300);

    }

    return 0;

}