Really Terrible Word Search Creation Program

//2014 C. Lohr - I hereby place the following code into the public domain.
//You can use it for whatever you want or modify it however you want.
//It's probably riddled with bugs, so I can't promise it'll work for anything.

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

char * board;
const char * word;
const char * letters;
int letterslen;
int wordlen;
int w, h;
int hits = 0;

int CheckPlace( int x, int y )
{
    int i;

    if( x < 0 || y < 0 || x>=w || y >= h ) return 0;

    //check up.
    for( i = 0; i < wordlen; i++ )
    {
        if( y-i < 0 ) break;
        char c = board[x+(y-i)*w];
        if( c != word[i] ) break;
    }
    if( i == wordlen ) return 1;

    //Check up (reversed)
    for( i = 0; i < wordlen; i++ )
    {
        if( y-i < 0 ) break;
        char c = board[x+(y-i)*w];
        if( c != word[wordlen-i-1] ) break;
    }
    if( i == wordlen ) return 1;

    //check left.
    for( i = 0; i < wordlen; i++ )
    {
        if( x-i < 0 ) break;
        char c = board[(x-i)+y*w];
        if( c != word[i] ) break;
    }
    if( i == wordlen ) return 1;

    //check left (Reversed)
    for( i = 0; i < wordlen; i++ )
    {
        if( x-i < 0 ) break;
        char c = board[(x-i)+y*w];
        if( c != word[wordlen-i-1] ) break;
    }
    if( i == wordlen ) return 1;

    //check down.
    for( i = 0; i < wordlen; i++ )
    {
        if( y+i >= h ) break;
        char c = board[x+(y+i)*w];
        if( c != word[i] ) break;
    }
    if( i == wordlen ) return 1;

    //check right.
    for( i = 0; i < wordlen; i++ )
    {
        if( x+i >= w ) break;
        char c = board[(x+i)+y*w];
        if( c != word[i] ) break;
    }
    if( i == wordlen ) return 1;

    //check upleft.
    for( i = 0; i < wordlen; i++ )
    {
        if( x-i < 0 ) break;
        if( y-i < 0 ) break;
        char c = board[(x-i)+(y-i)*w];
        if( c != word[i] ) break;
    }
    if( i == wordlen ) return 1;

    //check upleft. (reversed)
    for( i = 0; i < wordlen; i++ )
    {
        if( x-i < 0 ) break;
        if( y-i < 0 ) break;
        char c = board[(x-i)+(y-i)*w];
        if( c != word[wordlen-i-1] ) break;
    }
    if( i == wordlen ) return 1;

    //check upright.
    for( i = 0; i < wordlen; i++ )
    {
        if( x+i >= w ) break;
        if( y-i < 0 ) break;
        char c = board[(x+i)+(y-i)*w];
        if( c != word[i] ) break;
    }
    if( i == wordlen ) return 1;

    //Check upright (reversed)
    for( i = 0; i < wordlen; i++ )
    {
        if( x+i >= w ) break;
        if( y-i < 0 ) break;
        char c = board[(x+i)+(y-i)*w];
        if( c != word[wordlen-i-1] ) break;
    }
    if( i == wordlen ) return 1;


    //check downleft.
    for( i = 0; i < wordlen; i++ )
    {
        if( x-i < 0 ) break;
        if( y+i >= h ) break;
        char c = board[(x-i)+(y+i)*w];
        if( c != word[i] ) break;
    }
    if( i == wordlen ) return 1;


    //check downright.
    for( i = 0; i < wordlen; i++ )
    {
        if( x+i >= w ) break;
        if( y+i >= h ) break;
        char c = board[(x+i)+(y+i)*w];
        if( c != word[i] ) break;
    }

    if( i == wordlen ) return 1;


    return 0;
}

int main( int argc, char ** argv )
{
    int x, y;
    int i = 0;

    if( argc < 5 )
    {
        fprintf( stderr, "Error: usage:  ./wordsearch [x] [y] [word] [letters]\n" );
        return -1;
    }

    w = atoi( argv[1] );
    h = atoi( argv[2] );
    word = argv[3];
    letters = argv[4];
    wordlen = strlen( word );
    letterslen = strlen( letters );
    board = malloc( w * h );
    memset( board, 0, w * h );

    for( i = 0; i < w*h; i++ )
    {
        x = i % w;
        y = i / w;

        board[i] = letters[rand()%letterslen];

        if( CheckPlace( x, y ) )
        {
            //Fail -- backup.
            board[i] = 0;
            int backtrack = rand()%100;
            float backt = pow((float)backtrack/80.0, 9.0f);
            i-=(int)backt+1;
            if( i < 0 ) i = 0;
            hits++;
            continue;
        }
    }

    printf( "HITS: %d\n", hits );

    for( y = 0; y < h; y++ )
    {
        for( x = 0; x < w; x++ )
        {
            printf( "%c ", board[x+y*w] );
        }
        printf( "\n" );
    }

    return 0;
}