How do you separate a single alphanumeric string into different groups of numbers and letters in c plus plus?

Answer 1

#include<iostream>

#include<sstream>

using namespace std;

string digits {"0123456789+-.,"};

bool is_number (const string& str)

{

if (str.find_first_not_of(digits) != str.npos)

return false;

// If a plus sign is present, it must be the first character.

size_t f = str.rfind ('+');

if (f!=0 && f!=str.npos)

return false;

// If a minus sign is present, it must be the first character.

f = str.rfind ('-');

if (f!=0 && f!=str.npos)

return false;

// There can only be one decimal point at most.

size_t dot = str.find ('.');

if (dot != str.rfind ('.'))

return false;

// If a decimal point is present, it must not be the last character.

if (dot str.npos && comma != str.npos && (str.size()-comma)%4)

return false;

return true;

}

string get_first_number (const string& str)

{

for (auto b=str.begin(); b!=str.end(); ++b)

{

if (digits.find (*b) != digits.npos)

{

for (auto e=str.rbegin(); e.base()!=b; ++e)

{

if (digits.find (*e) != digits.npos)

{

auto t = e.base();

string n = str.substr (b-str.begin(), t-b);

if (is_number (n))

return n;

}

}

}

}

return "";

}

int main()

{

string text {"This string has the numbers 42, 1,000,000, 5,0, +1, -2, 3.14 and .5."};

string number;

cout << "Original string: "" << text << """ << endl;

cout << "\nNumbers:\n";

while ((number=get_first_number (text)).size())

{

cout << number << endl;

size_t pos = text.find (number);

text.replace (pos, number.size(), "\n");

}

cout << "\nStrings:\n";

stringstream ss;

ss << text << '\n';

while (!ss.eof())

{

getline (ss, text, '\n');

if (text.size())

cout << '"' << text << '"' << endl;

}

cout << endl;

}