句子反转

先将字符串按空格拆分成字符串数组
String 中的 spilt（） 方法
再用个字符串倒叙输出就可以了
import java.util.*;

public class Main{
    public static void main(String [] args){
        Scanner sc=new Scanner(System.in);
        String str=sc.nextLine();
        printIt(str);
    }
   
    public static void printIt(String s){
        String []st=s.split(" ");
        String s1="";
        for(int i=st.length-1;i>=0;i--){
            s1=s1+st[i]+" ";
        }
        System.out.println(s1.trim());
    }
    
}

#include<iostream>
#include<stack>
#include<string>
using namespace std;
int main(){
    string s;
    stack<string> sstack;
    while(cin>>s){
        sstack.push(s);
    }
    while(sstack.size()!=1){
        cout<<sstack.top()<<" ";
        sstack.pop();
    }
    cout<<sstack.top()<<endl;
    return 0;
}

import java.util.Scanner;

public class StringUtil {

	//句子反转
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		while(in.hasNext()){
			String str = in.nextLine();
			String arr[] = str.split(" ");
			StringBuffer res = new StringBuffer();
			for(int i=arr.length-1; i>0; i--){
				res.append(arr[i]+" ");
			}
			res.append(arr[0]);
			System.out.println(res.toString());
		}
	}
}

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

int main() {
    string words;
    while (getline(cin, words)) {
        reverse(words.begin(), words.end());
        unsigned i = 0, j = i;
        while (i < words.size()) {
            while (i < words.size() && words[i] != ' ')
                ++i;
            reverse(words.begin() + j, words.begin() + i);
            j = ++i;
        }
        cout << words << endl;
    }
    return 0;
}

#include <iostream> 
#include <stack>
#include <string>

using namespace std;

int main()
{     string s;     stack<string> st;     while(cin>>s)          st.push(s);     while(st.size()!=1)     {         cout<<st.top()<<" ";         st.pop();     }     cout<<st.top()<<endl;     return 0;
}

	

/**
*1.先将整个字符串转成字符数组反转得到 mi xiao hello
*2.遍历这个字符数组，遇到空格或者到了尾部再做局部反转
*/
public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		String s = scanner.nextLine();
		char[] arr = s.toCharArray();
		for (int i=0; i<arr.length/2; i++) {	// 整体反转
			char temp = arr[i];
			arr[i] = arr[arr.length-1-i];
			arr[arr.length-1-i] = temp;
		}
//		System.out.println(new String(arr));
		int start = 0, end = 0;
		for (int i=0; i<arr.length; i++) {		// 局部反转
			if (arr[i]==' ' || i+1==arr.length) {
				if (arr[i]==' ')
					end = i-1;
				else if (i+1==arr.length)
					end = i;
				for (int j=start; j<(start+end+1)/2; j++) {
					char temp = arr[j];
					arr[j] = arr[start+end-j];
					arr[start+end-j] = temp;
				}
				start = i + 1;
			}
		}
		System.out.println(new String(arr));
	}

//首先将输入字符串整体逆序，然后再分别逆序每个单词，单词以空格为边界。
//需要注意的是最后一个单词也要逆序，可以最后单独处理。
#include<iostream>
#include<string>
using namespace std;

void Reverse(string &str, int start, int end)    //字符串整体逆序
{
	while (start < end)
	{
		swap(str[start], str[end]);
		start++;
		end--;
	}
}

int main()
{
	string str;
	while (getline(cin,str))
	{
		int len = str.length();
		if (len <= 1)
		  {
			cout << str << endl;
			continue;
		  }
		Reverse(str,0,len-1);   //字符串整体逆序，比如输入"hello xiao mi",逆序后变为"im oaix olleh"
		int index = 0;    //记录每个单词第一个字母的位置index,初始为0
		for (int i = 0; i < len; i++)
		{
			if (str[i] == ' ')   //找到第一个空格
			{
				Reverse(str, index, i - 1);    //将str中index到i-1位置之间的单词逆序，此时im变为mi
				index = i + 1;   //记录下一个待逆序单词的起始位置
			}
		}
		Reverse(str, index, len-1);   //处理最后一个单词
		cout << str << endl;
	}
}

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNext()){
            String str = scanner.nextLine();
            String[] strs = str.split(" ");
            for (int i = strs.length-1; i >= 0; i--) {
                System.out.print(strs[i]);
                if(i != 0){
                    System.out.print(" ");
                }
            }
        }
    }
}

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

int main()
{
    string str1, temp;
    vector<string> v1;
    getline(cin, str1);
    for (int i = 0;i < str1.size();++i)
    {
        if (str1[i] != ' ')
            temp += str1[i];
        else
        {
            if (!temp.empty())
            {
                v1.push_back(temp);
                temp.clear();
            }
        }
    }
    if (!temp.empty())
        v1.push_back(temp);
    int i;
    for (i = v1.size() - 1;i > 0;--i)
        cout << v1[i] << ' ';
    cout << v1[i] << endl;
    return 0;
}

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

int main()
{
    int n,i=0,j,k;
    char s[1001],t[1001],c,temp;
    for(i=0;(c=getchar())!='\n';)
    {
        s[i++]=c;
    }
    s[i]='\0';
    i--;
    for(;i>=0;)//从句子尾部开始，遇到空格则抽离一个单词，得到的单词是倒序的，再通过一次反转
    {
        for(j=0;(s[i]!=' ')&&(i>=0);j++,i--)
        t[j]=s[i];
        t[j]='\0';
        j--;
        for(k=0;k<j;k++,j--)
        {
            temp=t[j];
            t[j]=t[k];
            t[k]=temp;
        }
        printf("%s",t);
        if(i<0) break;
        else {
                i--;
        printf(" ");}
    }
    printf("\n");
    return 0;
}

//...直接转换成数组翻转再连接成字符串
while(line = readline()){
    var lines = line.split(' ');
    var str = lines.reverse().join(' ');
    print(str);
}

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

int main(){
    string tmp,res; res="";
    while(cin>>tmp){res=tmp+" "+res;}
    cout<<res.substr(0,res.size()-1);
    return 0;
}

import java.util.Scanner;
public class Main{
 public static void main(String[] args) {
     String[] nextLine = new Scanner(System.in).nextLine().split(" ");
        StringBuilder stringBuilder = new StringBuilder();
        for (int i = nextLine.length-1; i >= 0; i--) {
            if (i==0) {
          stringBuilder.append(nextLine[i]);
   }else{
                stringBuilder.append(nextLine[i]+" ");
            }
      }
        System.out.println(stringBuilder);
     }
}

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

int main()
{     vector<string>a;     string temp;     char b;     while((cin>>temp).get(b)){         a.push_back(temp);         if(b=='\n')             break;     }     for(int i = 0;i<a.size();i++){         cout<<a[a.size()-1-i];         if(i!=a.size()-1)             cout<<" ";     }     system("pause");     return 0;
}

Python nice!

a = input().split()
a.reverse()
print(" ".join(a))

#include<iostream>
#include<string>
#include<sstream>

using namespace std;

int main()
{
    string line, result, word;
    while (getline(cin, line))
    {
        istringstream ism(line);
        ism >> result;
        while (ism >> word)
            result = word + " " + result;
        cout << result;
    }
    return 0;
}