Find char in string

[korbel]

I am starting to learn c++ by recreating my FreePascal code in C++

In the scenario below I am trying to cout the 3rd char in a given string, however the only thing returning is the number 112. am I doing something wrong?

#include <string>
#include <iostream>

using namespace std;

int dastrings (string line)
{

	return (line[2]);

}



int main ()
{
	
	cout << dastrings("poptarts \n") << endl;
	return 0;
	
}

[zb0S216C]

korbel wrote:

"however the only thing returning is the number 112. am I doing something wrong?"

That's to be expected. Each character in C++ is secretly an integer (represented in decimal format) that ranges from 0:127. When you pass a character to an int, the compiler assigns the character's integral equivalent to the int. C++ follows the ASCII character table, which can be found here: http://www.asciitable.com/

To fix this, swap int with char in dastrings() definition.

_Wazzak

[slicedpan]

The return type for the dastrings function should be char. At the moment it is returning an integer, and this is interpreted as a numerical value by the << operator. The function should return a char, which will be interpreted as an ascii character, and should print correctly.

[korbel]

@Framework

Yup that did the trick, and I just learned something new so golf claps all around.
A bit different from the function / procedure stuff I am used to. Thanks again!

[korbel]

So I ran into a new problem, and was hoping you could help me out again. I am getting another error while working this w/ strings, was wondering what I am doing wrong.

#include <string.h>
#include <iostream>
#include <stdio.h>

using namespace std;

char dastrings (string line, int lp)
{
	int i;
	char s;
	for ( i = 0; i <= lp; i++)
	{
		s= line[i];
	}
return ("placeholder");
}



int main ()
{
	string tmp = "poptarts";
	cout << dastrings(tmp, strlen(tmp) << endl;
	return 0;
	
}

[zb0S216C]

A char can only store a single character. To return a string, you have two options:

1) Return a pointer to a constant char: const char *

const char *ReturnAString() 
{
    return("A String");
}

2) Return a std::string

std::string ReturnAString()
{
    return("A String");
}

int main()
{
    std::string ReturnedString(ReturnAString());
    std::cout << "Size of the string: " << ReturnedString.length() << '\n';
}

I should point out that both "string.h" and "stdio.h" are C headers. "string.h" should be "string" and "stdio.h" should be "cstdio". Note the absence of file extensions. This is because C++ headers do not have extensions.

_Wazzak

[vlad from moscow]

Your code contains a bug.

Instead of

for ( i = 0; i <= lp; i++)

there should be

for ( i = 0; i < lp; i++)

in your function dastrings.

Otherwise when you call it the way dastrings(tmp, strlen(tmp) you are trying to access memory outside your string.

[korbel]

you are correct, however I didn't even get to that point since I am getting the following error when compiling

error: invalid conversion from ‘const char*’ to ‘char’ [-fpermissive]

[vlad from moscow]

This was already explained by Framework. String liiteral has type const char[] which can not be converted to char

You could write for example

return ("placeholder"[0] );

However I do not see any sense in your return value.

[korbel]

My apologize, I missed his reply, thank you.

[chipp]

what's your code?

[korbel]

Thank you again Framework, it compiled and worked
So now I know that you cannot mix char and string, which is just silly, but if I just stick to strings then I think my conversion will go smoother. Good thing almost everyone has like 2 gigs of ram these days.

#include <string.h>
#include <iostream>
#include <stdio.h>

using namespace std;

string dastrings (string line, int lp)
{
	int i;
	string s;
	bool foundone = false;

	for ( i = 0; i < lp; i++)
	{
		s = line[i];
		if (s == "@") { foundone = true; }
	}
	
	if (foundone == true)
	{ return ("ready"); }
	else { return ("end"); }
}



int main ()
{
	string tmp = "poptarts";
	cout << dastrings(tmp, tmp.length()) << endl;

	return 0;
	
}

[atrium]

 

[korbel]

You are right, I started reading "how to convert char to string" and saw there is a process for doing that. Coming from Delphi and Freepascal I can tell that c++ is much more finicky, but there is way more code examples, documentation and great people willing to help so it really is not all bad. I have dated some rigid women with very specific demands and this is a lot like that. :-)

[chipp]

hmm... talking about women... :)