Going to the new c++11 standards [closed] - c++

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CODE-JAM 2010 PROBLEM:
Given a list of space separated words, reverse the order of the words.
INPUT:
The first line of input gives the number of cases, N. N test
cases follow.
OUTPUT:
For each test case, output one line containing "Case #x: "
followed by the list of words in reverse order.
Limits:
N <= 5
INPUT:
3
this is a test
foobar
all your base
OUTPUT:
Case #1: test a is this
Case #2: foobar
Case #3: base your all
#include<iostream.h>
#include<conio.h>
#include<fstream.h>
#include<string.h>
#include<stdlib.h>
#include<stdio.h>
class prog {
char str[50];
public:
void getdata()
{
gets(str);
}
void rev();
void srev();
void display()
{
cout<< str;
}
};
void prog::srev()
{
int i,j,len;
char temp;
len=strlen(str);
for(i=0,j=len-1;i<len/2;i++,j--)
{
temp=str[i];
str[i]=str[j];
str[j]=temp;
}
}
void prog::rev()
{
int i,k=0;
char word[50];
strcat(str," ");
for(i=0;str[i]!='\0';i++)
{
if(str[i]!=' ')
{
word[k]=str[i];
k++;
}
else
{
while(k>0)
{
cout<<word[--k];
}
cout<<str[i];
}
}
}
void main()
{ clrscr();
fstream file;
int n;
cout<<"\n\n\t";
cin>>n;
prog p[10];
file.open("cj.txt",ios::in|ios::out|ios::binary);
for(int i=0;i<n;i++)
{
cout<<"\n\t";
p[i].getdata();
file.write((char*)&p[i],sizeof(p[i]));
}
file.seekg(0);
for(i=0;i<n;i++)
{
cout<<"\n\n\t";
p[i].srev();
p[i].rev();
}
}
I wrote this program in c++98 version, with turbo 3.0 as the IDE. It worked fine giving the desired ouput in the desired limits.
My question is, as C++ has rolled out C++11 Standard, what changes I have to do in my above code?
Also, can anyone provide me some good links to read out about the exact implementations in the libraries, as the changes must be innumerous, at one place?

Answer 1

For a more idiomatic approach, please see Reversing order of words in a sentence. I modified Stefan's answer a little bit:
#include <string>
#include <sstream>
#include <vector>
#include <algorithm>
#include <iostream>
#include <iterator>
int main()
{
std::string sentence = "Your sentence which contains ten words, two of them numbers";
std::istringstream stream(sentence);
std::vector<std::string> words;
std::copy(std::istream_iterator<std::string>(stream),
std::istream_iterator<std::string>(),
std::back_inserter(words));
std::reverse(words.begin(), words.end());
for ( size_t i(0); i < words.size(); ++i )
{
std::cout << words[i] << " ";
}
std::cout << "\n";
}
Also, since the problem from what I understand specifies a max amount of letters/words that will be given, you can get rid of std::reverse:
words.resize(20); // replace 20 with max amount
std::copy(std::istream_iterator<std::string>(stream),
std::istream_iterator<std::string>(),
words.rbegin());
Two other contrived examples:
std::reverse_copy(words.begin(), words.end(), std::ostream_iterator<std::string>(std::cout, " "));
std::copy(words.rbegin(), words.rend(), std::ostream_iterator<std::string>(std::cout, " "));

Answer 2

Your code needs considerable revision to follow C++98. At least offhand, I don't see any reason it would need further revision to follow C++11, though you might be able to make the code a little more readable using some of the new features of C++11.
In C++98/03, I'd probably write the code something like this:
int main() {
int num;
std::cin >> num;
for (int i=0; i<num; i++) {
std::string line;
std::getline(line, std::cin);
std::istringstream in(line);
std::vector<std::string> words((std::istream_iterator<std::string>(in)),
std::istream_iterator<std::string>());
std::copy(words.rbegin(), words.rend(),
std::ostream_iterator<std::string>(std::cout, " "));
}
}
In going to C++11, the primary change I'd make would be to use "uniform initialization":
std::vector<std::string> words{std::istream_iterator<std::string>(in),
std::istream_iterator<std::string>()};
A few people have written code to (for one example) use a range-based for loop in cases like this, so the loop would end up something like:
for (auto i : range(0, num))
I guess if you had a lot of other code that could use this, it might be worthwhile, but I see little point in it for one loop.