#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

#define BUF_LEN 20
#define BUF_INCR 10

int main(void)
{
    size_t buf_len  = BUF_LEN;
    char *buffer = (char*)malloc(buf_len);
    char *temp =NULL;
    char *pbuffer1 = buffer;
    char *pbuffer2 = NULL;

    printf("Enter:\n");
    
    //经典代码1，运行期动态分配内存
    while((*pbuffer1++=getchar())!=‘\n‘)
    {
        if((pbuffer1-buffer)==buf_len)
        {
            buf_len+=BUF_INCR;
            if(!(temp = realloc(buffer,buf_len)))
            {
                printf("bullshit!");
                exit(1);
            }
            pbuffer1 = temp + (pbuffer1 - buffer);
            buffer = temp;
            temp = NULL;
        }
    }

    *pbuffer1 = ‘\0‘;
    pbuffer1 = pbuffer2 = buffer;
    
    //经典代码段2，设置两个指针，对字符串进行操作，第三个指针进行全输出。
    while((*pbuffer1)!=‘\0‘)
    {
        if(ispunct(*pbuffer1)||isspace(*pbuffer1))
        {
            *pbuffer1++;
            continue;
        }
        else
            *pbuffer2++ = *pbuffer1++;
    }

    *pbuffer2 = ‘\0‘;
    printf("With the spaces and punctuation removed, the string is now:\n%s\n", buffer);
      free(buffer);
    return 0;
}