Given an input string which is comma-separated instead of space, the task is to parse this input string in C++.
First, let us understand what difference does it create if the input string is comma-separated.
Taking input a whitespace-separated string
Taking input a whitespace-separated string in C++ is very easy. The program to do so is:
#include <bits/stdc++.h> using namespace std;
int main()
{ string str;
// Get the string
getline(cin, str);
// Print the words
cout << str;
} |
1 2 3 4 5 6
Output:
1 2 3 4 5 6
Why can’t we use the above code for comma-separated input string?
The above code works fine for a whitespace-separated input string, but for a comma-separated input string, it won’t work as expected, because the program will take complete input as a single word in the string.
1, 2, 3, 4, 5, 6
Output:
1, 2, 3, 4, 5, 6
How to input a comma separated string?
Now inorder to input a comma separated string, following approach can be used:
- Get the string to be taken as input in stringstream
- Take each character of the string one by one from the stream
- Check if this character is a comma (‘, ‘).
- If yes, then ignore that character.
- Else, Insert this character in the vector which stores the words
Below is the implementation of the above approach:
// C++ program to input // a comma separated string #include <bits/stdc++.h> using namespace std;
int main()
{ // Get the string
string str = "11,21,31,41,51,61" ;
vector< int > v;
// Get the string to be taken
// as input in stringstream
stringstream ss(str);
// Parse the string
for ( int i; ss >> i;) {
v.push_back(i);
if (ss.peek() == ',' )
ss.ignore();
}
// Print the words
for ( size_t i = 0; i < v.size(); i++)
cout << v[i] << endl;
} |
11 21 31 41 51 61
Time complexity: O(N).
Auxiliary Space: O(N).