7.cpp

编译原理的上机要求

//统计标识符的个数
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#define BASELEN 10
#define INCRENTMENT 10

void main()
{
	char *p;
	FILE *fp;
	unsigned int Count=0;
	int i=0;
	int CurLen=0;
	int MaxLen=BASELEN;
	clrscr();
	if (!(fp=fopen("c:\\2.txt","r")))
	{
		printf ("Open file error.\n");
		exit(0);
	}
	if (!(p=(char*)malloc(sizeof(char)*BASELEN)))
	{
		printf ("Malloc Error.\n");
	}
	while(1)
	{
		if (CurLen==MaxLen)
		{
			MaxLen=MaxLen+INCRENTMENT;
			if (!(p=(char *)realloc(p,sizeof(char)*MaxLen)))
			{
				printf ("Realloc error.\n");
			}
		}
		fscanf(fp,"%c",p+i);
		if (*(p+i)=='\n') break;
		CurLen++;i++;
	}
	i=0;
	while(1)
	{
		if (*(p+i)=='\n') break;
		if (*(p+i)>='a' && *(p+i)<='z')
		{
			for(;(*(p+i)>='a' && *(p+i)<='z' || *(p+i)>='0' && *(p+i)<='9');i++)
			{
				printf ("%c",*(p+i));
			}
			Count++;
			printf ("\n");
			if (*(p+i)=='\n') break;
		}
		i++;
	}
	printf ("Count:%d\n",Count);
	fclose(fp);
	free(p);
}