/*
You could use counter as an index to a character array instead of a big clunky repetitive switch. If you have a char *spinner = "|/-\\";, spinner[0] will be "|", spinner[1] will be "/", etc.

char *spinner = "|/-\\"; printf("\b%c", spinner[counter]); is going to print the common backspace character and the correct "spinner symbol" for each value of counter. The spinner variable does not need to be declared because it's a string literal: printf("%c", "|/-\\"[counter]); can be used instead.
*/


    #ifdef _WIN32
        #include <windows.h>
        #define sleepThr(x) Sleep(x)
    #else
        #include <unistd.h>
        #define sleepThr(x) usleep((x) * 1000)
    #endif

    #include <stdio.h>

    #define INTERVAL 200

    int main()
    {
        int counter;
        while (1)
        {
            for (counter = 0; counter < 4; counter++)
            {
                printf("\b%c", "|/-\\"[counter]);
                fflush(stdout);
                sleepThr(INTERVAL);
            }
        }

        return 0;
    }