Move the cursor in a C program

Question

I\'d like to move the cursor forward and backwards in a C program. I\'m reading the whole line in a loop, but i would like that if a cursor key gets pressed the cursor on th

Answer 1

A simple example using ANSI escape sequences:

#include 


int main()
{
    char *string = "this is a string";
    char input[1024] = { 0 };
    printf("%s", string);
    /* move the cursor back 5 spaces */
    printf("\033[D");
    printf("\033[D");
    printf("\033[D");
    printf("\033[D");
    printf("\033[D");
    fgets(input, 1024, stdin);
    return 0;
}

To do very much useful the terminal needs to be put into canonical mode with termios.h and/or curses.h/ncurses.h. This way the backspace key code can be caught and responded to immediately and the buffer drawn to screen accordingly. Here is an example of how to set the terminal into canonical mode with tcsetattr():

struct termios info;
tcgetattr(0, &info);
info.c_lflag &= ~ICANON;
info.c_cc[VMIN] = 1;
info.c_cc[VTIME] = 0;
tcsetattr(0, TCSANOW, &info);

Another option might be to use the readline() or editline() library. To use the readline library specify -lreadline to your compiler. The following code snippet can be compiled with

cc -lreadline some.c -o some


#include 

#include 
#include 

int main()
{
    char *inpt;
    int i = 0;

    while ( i < 10 )
    {
        inpt = readline("Enter text: ");
        add_history(inpt);
        printf("%s", inpt);
        printf("\n");
        ++i;
    }
    return 0;

}