Example: Input: "prodevelopertutorial is a good website", Output: " website good a is prodevelopertutorial".
The solution is as follows:
Step 1: Reverse the whole string.
Step 2: Reverse individual words in the string.
Along with the above 2 steps, we need to remove leading and trailing spaces, and extra spaces in between the words.
Solution in C++
#include<iostream>
#include<string.h>
#include<algorithm>
using namespace std;
void reverseWords(string &str)
{
int start = 0;
int i = 0;
cout<<"\n\n============debugging logs start===========";
//remove leading space
while( str[i] == ' ') str.erase(i, 1);
cout<<"\nStep 1 after removing leading space = "<<str<<endl;
//reverse words
reverse(str.begin(), str.end());
cout<<"Step 2 after reversing the words = "<<str<<endl;
//remove trailing zeros
while( str[i] == ' ') str.erase(i, 1);
cout<<"Step 3 after trailing zeros= "<<str<<endl;
int size = str.size();
for(i = 0; i < size - 1; i++)
{
//check if you encounter a space.
// if you encounter a space, then it is a word, reverse the word.
if( str[i] == ' ')
{
if( i == start )
{
// if there is more than one space between two words, remove extra space
str.erase(i--,1);
size--;
cout<<"Step 4 removing extra space between words = "<<str<<endl;
}
else
{
// reverse word.
reverse(str.begin()+start, str.begin()+i);
start = i+1;
cout<<"Step 5 reversing single word = "<<str<<endl;
}
}
}
// reverse the last word.
reverse(str.begin() + start, str.end());
cout<<"Step 6 reversing last word = "<<str<<endl;
cout<<"============debugging logs end===========\n\n"<<endl;
}
int main()
{
string str = " Hello world from prodevelopertutorial.com ";
cout<<"\nOriginal string = "<<endl;
cout<<"\""<< str <<"\"";
reverseWords(str);
cout<<"String after reversing words = "<<endl;
cout<<str<<endl;
return 0;
}Output:
Original string = " Hello world from prodevelopertutorial.com " ============debugging logs start=========== Step 1 after removing leading space = Hello world from prodevelopertutorial.com Step 2 after reversing the words = moc.lairotutrepolevedorp morf dlrow olleH Step 3 after trailing zeros= moc.lairotutrepolevedorp morf dlrow olleH Step 5 reversing single word = prodevelopertutorial.com morf dlrow olleH Step 4 removing extra space between words = prodevelopertutorial.com morf dlrow olleH Step 4 removing extra space between words = prodevelopertutorial.com morf dlrow olleH Step 4 removing extra space between words = prodevelopertutorial.com morf dlrow olleH Step 5 reversing single word = prodevelopertutorial.com from dlrow olleH Step 4 removing extra space between words = prodevelopertutorial.com from dlrow olleH Step 4 removing extra space between words = prodevelopertutorial.com from dlrow olleH Step 5 reversing single word = prodevelopertutorial.com from world olleH Step 4 removing extra space between words = prodevelopertutorial.com from world olleH Step 4 removing extra space between words = prodevelopertutorial.com from world olleH Step 4 removing extra space between words = prodevelopertutorial.com from world olleH Step 6 reversing last word = prodevelopertutorial.com from world Hello ============debugging logs end=========== String after reversing words = prodevelopertutorial.com from world Hello
