decipher.c

一个用C编写的简单的关系数据库系统

int decipher(char * commond)
{
	char * getstr, * tokenPtr;
	int commond_count = 0;/*记录命令行数*/

	getstr = (char *)malloc(MAX_COMMOND_LENGTH * sizeof(char));
	tokenPtr = (char *)malloc(MAX_COMMOND_LENGTH * sizeof(char));
	gets(getstr);
	if (!isalnum(*getstr))
		gets(getstr);
	commond_count++;	

	commond = strcpy(commond,getstr);
	while(getstr[strlen(getstr)-1] != ';')
	{
		if (commond_count > MAX_COMMOND_COUNT) {
			puts("	 错误，输入的命令已超过20行!!!");
			return ERROR;
		}
		printf("          ");
		gets(getstr);
		commond = strcat(commond, " ");
		commond = strcat(commond, getstr);
		commond_count++;
	}
	/*除去最后的；号*/
	commond[strlen(commond)-1] = '\0';

	tokenPtr = strcpy(tokenPtr, commond);
	tokenPtr = strtok(tokenPtr, " ");
	if (strcmpi(tokenPtr,"HELP") == 0)
		return HELP;
	if (strcmpi(tokenPtr,"EXIT") == 0)
		return EXIT;
	if (strcmpi(tokenPtr, "CREATE") == 0) 
		return CREATE;
	if (strcmpi(tokenPtr, "OPEN") == 0) 
		return OPEN;
	if (strcmpi(tokenPtr, "CLOSE") == 0)
		return CLOSE;
	if (strcmpi(tokenPtr, "USE") == 0)
		return USE;
	if (strcmpi(tokenPtr, "INSERT") == 0)
		return INSERT;
	if (strcmpi(tokenPtr, "DELETE") == 0)
		return DELETE;
	if (strcmpi(tokenPtr, "SELECT") == 0)
		return SELECT;
	if (strcmpi(tokenPtr, "UPDATE") == 0)
		return UPDATE;
	if (strcmpi(tokenPtr, "SEEK") == 0)
		return SEEK;
	puts("错误命令格式!!!");
	return ERROR;
}