/* Set bit designated by index. */
var1 = var1 | ((unsigned char) 1 << index);

/* Clear bit designated by index */ 
var1 = var1 & ~((unsigned char) 1 << index); 

/* Copy bit designated by index to result. */
if(var1 & ((unsigned char) 1 << index))
    {
    result = 1;
    }
else
    {
    result = 0;
    }