C ++返回char *问题 [英] C++ return char* problem

问题描述

你好！

我在函数中返回char *时遇到问题。

即时尝试构建一个获取字符串（少量单词）和单词编号的函数。

这个函数需要返回指定单词的指针。



例如：

  char  string [] =   Hello World; 
  char  * Pstring = string; 
  int  num =  2 ; 
  char  * word; 
 word = myfunction（Pstring，num）; 
 cout<< word; 

，结果将是

世界

现在好像我不能返回Pstring [i]而我不知道为什么..

我的算法找到了所需单词的索引，但我找不到一种方法将其位置作为指针返回。



希望很清楚，谢谢！



我尝试过：



这是我的功能

  int  i =  0 ，flag =  0 ; 
  //  搜索字位置;  
  for （; num> 0; i ++）{
  if （pstring [i]< =  122 && pstring [i]> =  65 ）{
 flag =  1 ; 
} 
 其他  if （flag&&（Pstring [i] == ' ' || Pstring [i] ==  ' ，' || Pstring [i] == ' 。'））{
 num--; 
 flag =  0 ; 
} 
} 
  return  Pstring [i]; 

解决方案

Pstring是一个指向char的指针 - 或者是一个字符串，如果你愿意的话。

Pstring [i] 是与说 *（Pstring + i） whingbis 相同，这是字符串的单个元素：一个字符。

因为你的函数应该返回一个指向一个字符的指针，所以它不起作用！

有两种方法可以用你现有的代码返回：

  return &（Pstring [i]）; 

或

 返回 Pstring + i; 

但我会dump i 并使用PString作为指针而我增加了。



拼写错误[/ edit]

hello!
im having a problem returning char* in a function.
im trying to build a function that getting a string (with few words) and word number.
this function needs to return a pointer of the specified word.

for example:

char string[]="Hello World";
char* Pstring=string;
int num=2;
char* word;
word=myfunction(Pstring,num);
cout<<word;

and the results will be

World

now it seems that i cant return Pstring[i] and i dont know why..
my algorithm finds the index of the needed word but i just cant find a way to return his location as a pointer.

hope it was clear, thanks !

What I have tried:

this is my function

int i=0,flag=0;	
// search for word location;
	for(;num>0;i++){
		if(pstring[i]<=122 && pstring[i]>=65){
			flag=1;
		}
		else if(flag &&( Pstring[i]==' '||Pstring[i]==','|| Pstring[i]=='.')){
			num--;
			flag=0;
		}
	}
	return Pstring[i];

解决方案

Pstring is a pointer to a char - or a string, if you prefer.
Pstring[i] is the same as saying *(Pstring + i) whingbis which is a single element of the string: a character.
Since your function is supposed to return a pointer to a character, it doesn't work!
There are two ways to do the return with your existing code:

return &(Pstring[i]);

Or

return Pstring + i;

But I'd dump i and use PString as a pointer which I incremented instead.

[edit]typo[/edit]

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