Reading in unknown length of numbers - c++

Question

I have an input file that contains some data in coordinate mode
For example (2,3,5) translates to column 2, row 3, and level 5. I'm curious on a method of reading in the numbers after using getline(cin,string) to obtain the data. I don't know how many digits are in the data points so i can't assume the 1st character will be of length 1. Is there any libraries that can help solve the problem faster?
my gameplan so far that's not finished
void findNum(string *s){
int i;
int beginning =0;
bool foundBegin=0;
int end=0;
bool foundEnd=0
while(*s){
if(isNum(s)){//function that returns true if its a digit
if(!foundBegin){
foundBegin=1;
beginning=i;
}
}
if(foundBegin==1){
end=i;
foundBegin=0;
}
i++;
}
}

Answer 1

Try this:
#include <iostream>
#include <cstdlib>
#include <sstream>
#include <vector>
#include <string>
int main() {
std::vector <std::string> params;
std::string str;
std::cout << "Enter the parameter string: " << std::endl;
std::getline(cin, str);//use getline instead of cin here because you want to capture all the input which may or may not be whitespace delimited.
std::istringstream iss(str);
std::string temp;
while (std::getline(iss, temp, ',')) {
params.push_back(temp);
}
for (std::vector<std::string>::const_iterator it=params.begin(); it != params.end(); ++it) {
std::cout << *it << std::endl;
}
return 0;
}
The only caveat is that the arguments will have to be non whitespace delimited.
Example input string:
1,2,3
Output:
1
2
3
Once these arguments have been parsed, you can then convert them from strings to (example) integer via the following:
template <typename T>
T convertToType(const std::string &stringType) {
std::stringstream iss(stringType);
T rtn;
return iss >> rtn ? rtn : 0;
}
which can be used as follows:
int result = convertToType<int>("1");//which will assign result to a value of 1.
UPDATE:
This now works correctly on whitespace delimited input (except for newlines) like the following:
1 , 2, 3 , 4
Which yields:
1
2
3
4

Answer 2

jrd1's answer is pretty good, but if you'd prefer there happen to be functions for converting characters to integers (and back) already in the C standard library (cstdlib). You'd be looking for atoi.
http://en.cppreference.com/w/cpp/string/byte/atoi

Answer 3

#include <sstream>
void findNums(const string &str, int &i, int &j, int &k)
{
std::stringstream ss(str);
char c;
ss >> c >> i >> c >> j >> c >> k;
}

Answer 4

Simply use extractor operator for reading any type of value in respective variable type.
#incude<ifstream> // for reading from file
#include<iostream>
using namespace std;
int main()
{
int number;
ifstream fin ("YouFileName", std::ifstream::in);
fin >> number; // put next INT no matter how much digit it have in number
while(!fin.eof())
{
cout << number << endl;
fin >> number; // put next INT no matter how much digit it have in number and it will ignore all non-numeric characters between two numbers as well.
}
fin.close();
return 0;
}
Have a look over here for more details.
Note: Be careful while using it for character arrays and strings.. :)