String manipulation

[The Midnighter]

Alright, so I'm trying to write a fraction calculator for the hell of it, here's my problem:

I want the user to enter in two fractions, lets say 64/100 and 55/100
I want then to enter one fraction at a time, in exactly that format. How can I manipulate that string, so I can get the numbers separated by the '/' ?

I've been messing around with strings for a while now, but I can't seen to figure out how to separate it.. Thanks for the tips!

Edit: Okay, I've got some code written to find the /, now I just need to find out how to grab the numbers on either side of it...

// Written by Michael C. Dillon
#include <iostream>
#include <string>
#include <cstdlib>

using namespace std;
using std::string;

int main ()
{
	string first;
	char second[50];
	unsigned int value; 
	size_t found;

	while (true)
	{
	cout << "Enter your first fraction: ";
		getline(cin,first,'\n');
		string::size_type found = first.find("/", 0 );
			if (found!=string::npos)
				cout << "/ found at " << int(found) + 1 << endl;
	}

		system("PAUSE");
		return EXIT_SUCCESS;
}

[Ganon11]

Check out string::substr.

As a side note, why are you explicitly saying "using std::string", since you already say "using namespace std"?

[The Midnighter]

I'd delete this if I could!

[The Midnighter]

Check out string::substr.

As a side note, why are you explicitly saying "using std::string", since you already say "using namespace std"?

I lied, it wasn't quite what I needed xD
When I use that substr, its also copying the '/' into part of the variable, which is going to cause problems..
[CODE=CPP]
// Written by Michael C. Dillon
#include <iostream>
#include <string>
#include <cstdlib>

using namespace std;
using std::string;

int main ()
{
string first,str,str1;
char second[50];
unsigned int value;
size_t found;
size_t pos;

while (true)
{
cout << "Enter your first fraction (0 to exit): ";
getline(cin,fir st,'\n');
if (first=="0")
{
break;
}
else
{
pos = first.find('/');
str = first.substr(po s);
string::size_ty pe found = first.find("/" );
if (found!=string: :npos)
cout << "/ found at " << int(found) + 1 << "str = " << str;
}
}

system("PAUSE") ;
return EXIT_SUCCESS;
} [/CODE]


//// Edit

That was actually the easiest fix I've ever seen. I just added a +1 to (pos)
Thank god!

[weaknessforcats]

You might consider using a stringstream:
[code=cpp]
string str("54/100");
int numerator;
int denominator;
char trash;
stringstream ss;
ss << str;
ss >> numerator >>trash >> denominator;
cout << numerator << endl <<denominator << endl;
[/code]

[The Midnighter]

You might consider using a stringstream:
[code=cpp]
string str("54/100");
int numerator;
int denominator;
char trash;
stringstream ss;
ss << str;
ss >> numerator >>trash >> denominator;
cout << numerator << endl <<denominator << endl;
[/code]

... Didn't understand your code at all mate. Also didn't compile.

[The Midnighter]

Alright, so I've come to the conclusion that substr can find the variable for me after the /, but what about before the slash?

I was thinking, if I could count how many spaces there are from the beginning of the line, until the '/' - then I could do a string::find to shove that into a variable..
Here's my current code:
[CODE=cpp]// Written by Michael C. Dillon
#include <iostream>
#include <string>
#include <cstdlib>

using namespace std;
using std::string;

int main ()
{
string first,str,str1;
size_t pos;

while (true)
{
cout << "Enter your first fraction (0 to exit): ";
getline(cin,fir st,'\n');
if (first=="0")
{
break;
}
else
{
pos = first.find('/');
str = first.substr(po s+1);
cout << "pos = " << pos+1 << " str = " << str << ".";
//string::size_ty pe found = first.find("/" );
// if (found!=string: :npos)
// cout << "/ found at " << int(found) + 1 << "str = " << str;
}
}

system("PAUSE") ;
return EXIT_SUCCESS;
} [/CODE]

Ignore that commented out crap, I'm pretty sure its useless.

[weaknessforcats]

Didn't understand your code at all mate. Also didn't compile.

It most certainly does because I compiled an ran it before posting.

Probably you did not include the correct headers: <string> <sstream>.

As yo your understanding, I assume you know cin >> and cout <<. Yes?

Well, a stringstream is a variable that on the one hand acts like a stream so you can use the << and >> operators and on the other hand acts like a string.

This is called in-core formatting. A little Google should clear this up.

Hand-parsing a string is the hard way to go.