what is the best way to parse a string in c++ [closed] - c++

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How best to parse the following string in c++:
the input is a string, for example:
(someString1 45)(someString2 2432)(anotherString 55) // .... etc.
of course we are interested with the string-name and value..
our goal is to save the string and value in a map.
is there a automatic way to get the string inside the brackets ?
thank you,

Answer 1

A simple solution if your strings don't contain whitespace:
#include <iostream>
#include <string>
int main()
{
char c1, c2;
int n;
std::string s;
while (std::cin >> c1 >> s >> n >> c2 && c1 == '(' && c2 == ')')
{
std::cout << "Parse item: s = '" << s << "', number = " << n << "\n";
}
}
This method only works on correct input and has no way of recovering mid-way. If you need that, you can build something somewhat more elaborate using getline with ) as the separator.

Answer 2

The following will do the trick:
string some; int n;
string s = "(someString1 45)(someString2 2432)(anotherString 55)";
stringstream sst(s); // to parse the string
while (sst.get() == '(' && sst >> some >> n && sst.get()==')') {
cout << some << "," << n << endl;
}
This loop will not try to read some string and n if the open brace is not present.
A slight change could even allow to safely parse further input string if you'd expect something to follow the list of entries between braces:
string s = "(someString1 45)(someString2 2432)(anotherString 55)thats the rest";
...
while (sst.get() == '(') { // open brace to process
if (sst >> some >> n && sst.get() == ')')
cout << some << "," << n << endl; // succesful parse of elements
else {
cout << "Wrong format !!\n"; // something failed
if (!sst.fail()) sst.setf(ios::failbit); // case of missing closing brace
}
}
if (sst) { // if nothing failed, we are here because open brace was missing and there is still input
sst.unget(); // ready to parse the rest, including the char that was checked to be a brace
string rest;
getline(sst, rest);
cout << "The braces are followed by: " << rest << endl;
}