www.pudn.com > progs.zip > ch3-06.y

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main()
{
	extern double sqrt(), exp(), log();

	addfunc("sqrt", sqrt);
	addfunc("exp", exp);
	addfunc("log", log);
	yyparse();
}

addfunc(name, func)
char *name;
double (*func)();
{
	struct symtab *sp = symlook(name);
	sp->funcptr = func;
}