curses.c

// http://heather.cs.ucdavis.edu/~matloff/UnixAndC/CLanguage/Curses.pdf

// simple curses example; keeps drawing the inputted characters, in columns
// downward, shifting rightward when the last row is reached, and
// wrapping around when the rightmost column is reached

#include <curses.h>  // required

int r,c,  // current row and column (upper-left is (0,0))
    nrows,  // number of rows in window
    ncols;  // number of columns in window

void draw(char dc) {
    move(r,c);  // curses call to move cursor to row r, column c
    delch(); insch(dc);  // curses calls to replace character under cursor by dc
    refresh();  // curses call to update screen
    r++;  // go to next row
    // check for need to shift right or wrap around
    if (r == nrows)  {
        r = 0;
        c++;
        if (c == ncols) c = 0;
    }
}

int main(void) {
    int i;  char d;
    WINDOW *wnd;

    wnd = initscr();  // curses call to initialize window
    cbreak();  // curses call to set no waiting for Enter key
    noecho();  // curses call to set no echoing
    getmaxyx(wnd,nrows,ncols);  // curses call to find size of window
    clear();  // curses call to clear screen, send cursor to position (0,0)
    refresh();  // curses call to implement all changes since last refresh

    r = 0; c = 0;
    while (1)  {
        d = getch();  // curses call to input from keyboard
        if (d == 'q') break;  // quit?
        draw(d);  // draw the character
    }

    endwin();  // curses call to restore the original window and leave
}