题目：输入一个英文句子，翻转句子中单词的顺序，但单词内字符的顺序不变。句子中单词以空格符隔开。
比如：输入字符串： hello wolrd, welcome to china!
逆序后的结果：china! to welcome wolrd, hello
算法思想：首先将整个句子逆序，得到!anihc ot emoclew ,drlow olleh 然后分割每个单词，把每个单词逆序得到最终结果
源代码：
/*
sentence: 字符串
first: 字符串的起始位置
last: 字符串的结束位置
*/
void reverse(string &sentence, int first, int last)
{
int i = first;
char temp;
int j = 0;
//首尾字符交换
while(i < (first + (last - first) / 2))
{
temp = sentence[i];
sentence[i] = sentence[last - 1 - j];
sentence[last - 1 -j] = temp;
++i;
++j;
}
}
void reverseWords(string &sentence)
{
//把整个字符串逆序
reverse(sentence, 0, sentence.length());
int i = 0;
int j = i;
//把单个单词逆序
while(i < sentence.length())
{
if(sentence[i] == ' ')
{
reverse(sentence, j, i);
j = i+1;
}
++i;
}
//逆序最后一个单词
reverse(sentence, j, i);
}
int main()
{
string sentence;
cout << "input a sentence: ";
getline(cin, sentence);
cout << "sentence is: " << sentence << endl;
reverseWords(sentence);
cout << "After reverse words, the result is:" << sentence << endl;
system("Pause");
return 0;
}