将p所指字符串中每个单词的最后一个字母该成大写
eg:I am a student to take the examination.->
   I aM A studenT tO takE thE exanination.
#include<conio.h>
#include<ctype.h>
#include<stdio.h>
void fun(char *p)
{
 int k=0;
 for( ;*p; p++)
  if(k)
  {
  if(*p=='')
   {k=0;
    *(p-1)=toupper(*(p-1));
   }
  }
  else
   k=1;
}
main()
{
 char chrstr[64];
 int d;
 clrscr();
 printf("\nPlease enter an English sentence within 63 letters:");
 gets(chrstr);
 d=strlen(chrstr);
 chrstr[d]='';
 chrstr[d+1]=0;
 printf("\n\nBefore changing:\n %s",chrstr);
 fun(chrstr);
 printf("\nAfter changing:\n %s",chrstr);
} 有问题，应该怎么该？？

#include<conio.h>
#include<ctype.h>
#include<stdio.h>
void fun(char*p)
{
   // int k=0 ;
    for(;*p;p++)
    if(*p<'A'||(*p>'Z'&&*p<'a')||*p>'z')
    {
        if(*(p-1)>='a'&&*(p-1)<='z')*(p-1)-='a'-'A';
    }
    if(*(p-1)>='a'&&*(p-1)<='z')*(p-1)-='a'-'A';   //假如最后一个
}
main()
{
    char chrstr[64];
   // int d ;
    clrscr();
    printf("\nPlease enter an English sentence within 63 letters:");
    gets(chrstr);
   // d=strlen(chrstr);
    //chrstr[d]='' ;
   // chrstr[d+1]=0 ;
    printf("\n\nBefore changing:\n %s",chrstr);
    fun(chrstr);
    printf("\nAfter changing:\n %s",chrstr);
}