程序代码：

#include<stdio.h>
#include<stdlib.h>
#include<stdbool.h>
#include<string.h>

bool str_in(char **);
void str_sort(const char *[],int);
void swap(void **p1,void **p2);
void str_out(char *[],int);
const size_t BUFFER_LEN=256;
const size_t NUM_P=50;
int main(void)
{
    char *pS[NUM_P];
    int count=0;
    printf("\nEnter successive lines,pressing Enter at the end of" "each line.\nJust press Enter to end.\n");
    for(count=0;count<NUM_P;count++)
      if(!str_in(&pS[count]))
      break;
    str_sort( pS,count);    请指正这句出错原因  invalid conversion from `char**' to `const char**'
    str_out( pS,count);
    system("pause");
    return 0;
}
bool str_in(char **pString)
{
     char buffer[BUFFER_LEN];
     if(gets(buffer)==NULL)
       {
         printf("\nError reading string.\n");
         exit(1);
       }
     if(buffer[0]='\0')
      return false;
     *pString=(char*)malloc(strlen(buffer)+1);
     if(*pString==NULL)
     {
       printf("\nOut of menory.");
       exit(1);
     }
     strcpy(*pString,buffer);
     return true;
}

void str_sort(const char *p[],int n)
{
     char *pTemp=NULL;
     bool sorted=false;
     while(!sorted)
     {
       sorted=true;
       int i=0;
       for(i=0;i<n-1;i++)
         if(strcmp(p[i],p[i+1])>0)
         {
           sorted=false;
           swap(&p[i],&p[i+1]);//指向常量的指针只可以交换地址改变变量值，这句正确但是DEVC报错  invalid conversion from `char**' to `void**' initializing argument 1 of `void swap(void**, void**)'
         }
     }
}
void swap(void **p1,void **p2)
{
     void *pt=*p1;
     *p1=*p2;
     *p2=pt;
}
void str_out(char *p[],int n)
{
     printf("\nYour input sorted in older is :\n\n");
     int i=0;
     for(i=0;i<n;i++)
     {
       printf("%s",p[i]);
       free(p[i]);
       p[i]=NULL;
     }
     return;
}
            

程序代码：

#include<stdio.h>
#include<stdlib.h>
#include<stdbool.h>
#include<string.h>

bool str_in(char **);
void str_sort(char *[],int);
void swap(char **p1,char **p2);
void str_out(char *[],int);
const size_t BUFFER_LEN=256;
const size_t NUM_P=50;
int main(void)
{
    char *pS[NUM_P];
    int count=0;
    printf("\nEnter successive lines,pressing Enter at the end of" " each line.\nJust press Enter to end.\n");
    for(count=0;count<NUM_P;count++)
      if(!str_in(&pS[count]))//读入字符串
      break;
    str_sort( pS,count);    //按首字母排序str_in模块读入的字符串
    str_out( pS,count);     //输出排序后的字符串
    system("pause");
    return 0;
}
bool str_in(char **pString)  //用来读取字符串
{
     char buffer[BUFFER_LEN];
     if(gets(buffer)==NULL)
       {
         printf("\nError reading string.\n");
         return false;     //问题：读取字符串时，没有办法控制读取的个数，导致一直在读取字符串，程序一直在执行这个模块
       }
     if(buffer[0]='\0')
      return false;
     *pString=(char*)malloc(strlen(buffer)+1);
     if(*pString==NULL)
     {
       printf("\nOut of menory.");
       exit(1);
     }
     strcpy(*pString,buffer);
     return true;
}
void str_sort(char *p[],int n)  
{
     char *pTemp=NULL;
     bool sorted=false;
     while(!sorted)
     {
       sorted=true;
       int i=0;
       for(i=0;i<n-1;i++)
         if(strcmp(p[i],p[i+1])>0)
         {
           sorted=false;
           swap(&p[i],&p[i+1]);
         }
     }
}
void swap(char **p1,char **p2)  //用来排序字符串
{
     char *pt=*p1;
     *p1=*p2;
     *p2=pt;
}
void str_out(char *p[],int n)
{
     printf("\nYour input sorted in older is :\n\n"); 
     int i=0;
     for(i=0;i<n;i++)
     {
       printf("%s\n",p[i]);  //问题：改写后的程序无法输出字符串
       free(p[i]);
       p[i]=NULL;
     }
     return;
}
             

while(str_in(&pS[count++])&&count<5);//读入字符串