字符串中字词的反序 [英] Reverse order of words in string

问题描述

我正在准备一个入门级的面试。我试图扭转字符串中的单词的顺序，但我的输出是一堆垃圾，没有意义。我认为问题可能是因为我使用char *我的功能？反正我的代码

I am preparing for an entry-level job interview. I am trying to reverse the order of words in a string, but my output is a bunch of junk that makes no sense. I think the problem may be because I'm using "char*" for my functions? Anyways, heres my code

#include <iostream>
#include <string>
using namespace std;

char* reverse(char* str, int a, int b); 
char* reversewords(char* str); 

int main()
{
    char str[] = "The interview is";
    cout<<"Reverse is: "<<reversewords(str); 
    cin.ignore();
    return 0;
}


char* reverse(char* str, int a, int b)
{
    int length = a-b;

    for (int i=a; i<b+1; i++)
    {
        char c =str[length-i-1];
        str[length-i-1]=str[i];
        str[i] = c;
    }
    return str;
}

char* reversewords(char* str)
{
    int length = strlen(str);
    int a=0;
    int b=0;
    while (b<length)
    {
        if (str[b]==' ' || b==length-1)
        {
                b=b-1;
            reverse(str, a, b);
            a=b+2;
            b=a;
        }
        b++;
    }
    return str;
}

推荐答案

WeaselFox说不要重新发明轮子，尝试学习C ++ STL，从长远来看会更有帮助。

I would like to reiterate what WeaselFox said about not reinventing the wheel, try to learn the C++ STL, in the long run that will be a lot more helpful.

说到这里，让我建议一种方法以及。每当你遇到像字符串中的字符倒序或字符串中的字符颠倒的问题，采访者真的试图测试你的数据结构的知识，在这种情况下，特别是堆栈数据结构。

Having said that let me suggest an approach as well. Whenever you come across problems like reversing order of chars in a string OR reversing words in a string, interviewers are really trying to test your knowledge of data structures, and in this case, specifically the "stack" data structure.

考虑如果你解析一个字符串中的单词并将它们一次放入一个数组，会发生什么：
I AM A STRING - > {I AM，A，STRING}

Consider what happens if you parse words in a string and place them all into an array one at a time: "I AM A STRING" --> {"I", "AM", "A", "STRING"}

现在为堆叠做同样的事情：

Now do the same thing for a stack:

I AM A STRING - > {STRING，A，AM，I}

"I AM A STRING" --> {"STRING", "A", "AM", "I"}

有用吗？如果你自己比我提供源代码更好，原因是你的方法是不正确的，无论是否产生正确的答案。

Do you see why a stack would be useful ? It's better if you reason it out yourself than I provide source code, the reason being that your approach is incorrect regardless of whether or not it yields the correct answer.

我希望这有助于！

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