#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define USAGE() printf("USAGE: abbr \"sentence\"\n")

int main(int argc, const char** args)
{
    if(argc == 2)
    {
        // Make a char array half the length of
        // the input string to make sure it's long
        // enough
        char initials[strlen(args[1]) / 2],
            chr;

        // A boolean to mark the next loop as an initial
        short next = 1;

        // Variables to keep track of index
        int strcount = 0, initcount = 0;

        // Browse through every char
        while(chr = args[1][strcount])
        {
            // Increase index
            strcount++;

            // If we see a space character, mark the
            // next character as an initial
            if(chr == ' ' && strcount > 0)
            {
                next = 1;
                continue;
            }

            // If marked as an initial
            if(next)
            {
                initials[initcount] = chr;
                next = 0;
                initcount++;
            }
        }

        // Nullbyte!
        initials[initcount] = '\0';

        // Print out the initials
        printf("%s\n", initials);
    }
    else USAGE();
}