Isolating numbers from a string.

[fidelcashflo]

Hello, for my assignment, we have to read in a file which contains a series of numbers. The file will look like this:

i1 i2 i3 i4 i5 d6 i7 d8 i999

The sequence will be random. Every integer will have only "i" or "d" in front of it.

We have to write a program that will output something like this:

I = 1
I = 2
I = 3
I = 4
I = 5 
D = 6
…

I have written a program that works, but it only works if there is a space between the character and the number.

Such as:

i 1 i 2 i 3...

My question is how can I make my program work without having to put the spaces in between the character and the numbers?

Here is my code so far:

#include <iostream>
#include <string>
#include <fstream>
using namespace std;

void RunList(string a);

int main(){
        string name;

        // Ask for filename and send it to function.
        cout << "Filename >> ";
        cin >> name;
        RunList(name);

	system("pause");
        return 0;
}

void RunList(string a){
        // Open file for reading
        ifstream data;
        data.open(a.c_str());
        string stuff;

        // Read file till EOF
        while(data >> stuff){
                int in;

                data >> in;
                if(stuff == "i"){
                        cout << "I = " << in << endl;;
		}
                // If "d" is encountered
                else if(stuff == "d"){
                        cout << "D = " << in << endl;
                }

		data.clear();
        }

}

Thanks.

[Stewbond]

Get rid of the spaces. Extract the first element of the string. That's your prefix. Then the rest of the string needs to be converted to a number. Stringstreams are useful for this:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

// Read file till EOF while(data >> stuff){ char prefix = stuff[0]; string number(stuff.begin()+1, stuff.end()); stringstream iss(number); int in; iss >> in; if(prefix == 'i'){ cout << "I = " << in << endl;; } // If "d" is encountered else if(prefix == 'd'){ cout << "D = " << in << endl; } data.clear(); }

stuff = "i1" prefix = 'i' number = "1" Now we need to convert it to a number stick it in a stream in = 1

[fidelcashflo]

Thank you, that did it!