How to get input an array of strings with \n as delimiter? - c++

Question

#include<bits/stdc++.h>
using namespace std;
int main()
{
int i=0;
char a[100][100];
do {
cin>>a[i];
i++;
}while( strcmp(a[i],"\n") !=0 );
for(int j=0;j<i;i++)
{
cout<<a[i]<<endl;
}
return 0;
}
Here , i want to exit the do while loop as the users hits enter .But, the code doesn't come out of the loop..

Answer 1

The following reads one line and splits it on white-space. This code is not something one would normally expect a beginner to write from scratch. However, searching on Duckduckgo or Stackoverflow will reveal lots of variations on this theme. When progamming, know that you are probably not the first to need the functionality you seek. The engineering way is to find the best and learn from it. Study the code below. From one tiny example, you will learn about getline, string-streams, iterators, copy, back_inserter, and more. What a bargain!
#include <iostream>
#include <string>
#include <sstream>
#include <algorithm>
#include <iterator>
#include <vector>
int main() {
using namespace std;
vector<string> tokens;
{
string line;
getline(cin, line);
istringstream stream(line);
copy(istream_iterator<string>(stream),
istream_iterator<string>(),
back_inserter(tokens));
}
for (auto s : tokens) {
cout << s << '\n';
}
return 0;
}

Answer 2

First of all, we need to read the line until the '\n' character, which we can do with getline(). The extraction operator >> won't work here, since it will also stop reading input upon reaching a space. Once we get the whole line, we can put it into a stringstream and use cin >> str or getline(cin, str, ' ') to read the individual strings.
Another approach might be to take advantage of the fact that the extraction operator will leave the delimiter in the stream. We can then check if it's a '\n' with cin.peek().
Here's the code for the first approach:
#include <iostream> //include the standard library files individually
#include <vector> //#include <bits/stdc++.h> is terrible practice.
#include <sstream>
int main()
{
std::vector<std::string> words; //vector to store the strings
std::string line;
std::getline(std::cin, line); //get the whole line
std::stringstream ss(line); //create stringstream containing the line
std::string str;
while(std::getline(ss, str, ' ')) //loops until the input fails (when ss is empty)
{
words.push_back(str);
}
for(std::string &s : words)
{
std::cout << s << '\n';
}
}
And for the second approach:
#include <iostream> //include the standard library files individually
#include <vector> //#include <bits/stdc++.h> is terrible practice.
int main()
{
std::vector<std::string> words; //vector to store the strings
while(std::cin.peek() != '\n') //loop until next character to be read is '\n'
{
std::string str; //read a word
std::cin >> str;
words.push_back(str);
}
for(std::string &s : words)
{
std::cout << s << '\n';
}
}

Answer 3

You canuse getline to read ENTER, run on windows:
//#include<bits/stdc++.h>
#include <iostream>
#include <string> // for getline()
using namespace std;
int main()
{
int i = 0;
char a[100][100];
string temp;
do {
getline(std::cin, temp);
if (temp.empty())
break;
strcpy_s(a[i], temp.substr(0, 100).c_str());
} while (++i < 100);
for (int j = 0; j<i; j++)
{
cout << a[j] << endl;
}
return 0;
}
While each getline will got a whole line, like "hello world" will be read once, you can split it, just see this post.