int main(int argc, char * argv[])
{
    if (argc == 1)		//without arguments
    {
        printf("\nOperating Systems Lab1 -- Linker.\n");
        printf("Author: Luxiang Yin (c)\n\n");
        printf("Usage:\n\t%s [Input File]\n\n", argv[0]);
        return -1;
    }
    else if(argc == 2)
    {
        MODULE_t * MT = NULL;
        FILE * f = fopen(argv[1], "r");
        if (!f)
        {
            printf("File open error.\nPlease make sure the file exists,\n");
            printf("and you have the permission to read it.\n");
            return -1;
        }

        if (PassOne(f, &MT) == 0)
        {
            PassTwo(f, MT);
            free(MT);
        }
        fclose(f);
    }
    else
    {
        printf("Too many arguments.\n");
        return -1;
    }

    return 0;
}
void main()
{
	clrscr();
	printf("\nEnter Source File Name: ");
	scanf("%s",SrcFile);
	PassOne();
	DispSymbTab();
}