Remove a specific char and remove multiple spaces

Well right now this code Removes one specific letter from the string we give.
The problem is that i found this func code on google so i don't really understand it(I am very new to this)
I made the main's code myself.

1)I need some help to understand what

Code:

string str = phrase;

do???
2)Why when i put

Code:

cout << str << endl;

in main give me some random numbers??even if i change str with z, give me some other random numbers...
3)THIS IS THE MOST IMPORTANT even if u can't help with others.
I need to add in this code something that removes multiple spaces and leaves only ONE space.
This program in the end should
Take a String(Phrase) as an Input and a Letter to remove
Remove Multiple Spaces and leave only 1 space between each word
and give as the String(Phrase) with the specific letter removed and with only 1 space between each word.
EXAMPLE:
"What___a__great_____________weather__we have today" (consider underscore as a space because the forum doesn't let u put multiple spaces)
and lets say we want to remove "e"
SHOULD BECOME:
"What a grat wathr w hav"

Code:

#include <cstdlib> 
#include <iostream> 

using namespace std; 


int func(int i,char phrase[80]){ 
string str = phrase; 
char remove = i; 
for(string::iterator it = str.begin(); it!=str.end(); ){ 
if( (*it) == remove ) 
it = str.erase( it ); 
else 
it++; 
} 
cout << str << endl; 
} 


int main(int argc, char *argv[]) 
{ 
int i, n, z; 
char phrase[80]; 
printf("\nGive a Phrase "); 
gets(phrase); 
printf("\nThe Phrase is: "" %s\n"" ",phrase); 
printf("\nGive the letter you want to be removed "); 
scanf("%c",&i); 
z=func(i,phrase); 

system("PAUSE"); 
return EXIT_SUCCESS; 
}

string str = phrase; is just another way of writing the constructor call string str(phrase); which means you build a string object and use phrase as an initial value. There are several things wrong with this post, but foremost is that all the important changes happen to the string object, which is a copy of phrase, not the phrase variable. You should decide what you are going to use and fix that.

Code:

std::string RemoveChars(const std::string& Str, char Ch)
{
    std::string out;
    bool first = true;
    bool space = false;
    for (std::string::const_iterator it = Str.begin(); it != Str.end(); ++it)
    {
        if (*it == ' ')
        {
            if (first == false)
            {
                space = true;
            }
        }
        else if (*it != Ch)
        {
            if (space)
            {
                out.push_back(' ');
            }
            out.push_back(*it);
            space = false;
            first = false;
        }
        else
        {
            space = false;
        }
    }
    return out;
}

Input: "___xxx_____teeestx__aaa___x____" (ch = 'x')
Output: "teeest_aaa"

Originally Posted by stam

3)THIS IS THE MOST IMPORTANT even if u can't help with others.
I need to add in this code something that removes multiple spaces and leaves only ONE space.

Taking this as-is, kmdv's example is wrong, because it removes all leading and trailing spaces, rather than reducing them to a single space. Personally, I would suggest something like this:

Code:

namespace
{
    class IsConsecutiveSpace
    {
    public:
        bool operator()(char current, char previous) const
        {
            return previous == ' ' && current == previous;
        }
    };
}

std::string RemoveChars(const std::string& str, char ch)
{
    using namespace std;
    string out(str);
    string::iterator end = remove(out.begin(), out.end(), ch);
    out.erase(unique(out.begin(), end, IsConsecutiveSpace()), out.end());
    return out;
}

But of course, based on your earlier two questions, you probably don't understand what this does either

Basically, my idea is to make use of the std::remove algorithm to do exactly what you want: remove all the characters that match that one character provided. Then, I make use of the std::unique algorithm to remove consecutive spaces, leaving just one "unique" space.

Originally Posted by laserlight

Taking this as-is, kmdv's example is wrong, because it removes all leading and trailing spaces, rather than reducing them to a single space. Personally, I would suggest something like this:

I wasn't getting deeply into his problem, since it would take more time than writing this entire function.
About the validity: I think he wanted removing them as well, considering begin and end of string as whitespaces.

EDIT:

What is the function supposed to return for: x___test___x ?
_test_ or test? (laserlight's returns the first one, my the second one).

Boost has string algorithms for find and replace (something sorely missing in the standard library). Perhaps you should give them a go?

How is this problem find and replace? You don't replace anything.

Ah well, seeing as the number of consecutive spaces are unlimited, it may not work very well (seems I missed that part). But if you have a fixed amount, it should work very well.

Originally Posted by laserlight

Taking this as-is, kmdv's example is wrong, because it removes all leading and trailing spaces, rather than reducing them to a single space. Personally, I would suggest something like this:

Code:

namespace
{
    class IsConsecutiveSpace
    {
    public:
        bool operator()(char current, char previous) const
        {
            return previous == ' ' && current == previous;
        }
    };
}

std::string RemoveChars(const std::string& str, char ch)
{
    using namespace std;
    string out(str);
    string::iterator end = remove(out.begin(), out.end(), ch);
    out.erase(unique(out.begin(), end, IsConsecutiveSpace()), out.end());
    return out;
}

But of course, based on your earlier two questions, you probably don't understand what this does either

Basically, my idea is to make use of the std::remove algorithm to do exactly what you want: remove all the characters that match that one character provided. Then, I make use of the std::unique algorithm to remove consecutive spaces, leaving just one "unique" space.

Ok and how i am gonna give them the char a want to remove and the string i want to remove multiple spaces.
Its not like common functions.
Please explain i wanna learn something from this thing...

Perhaps this is a bit more along the lines of basic processing. You can function-ize it.

Code:

#include <iostream>
#include <string> 

using namespace std ; 

int main (int argc, char * const argv[]) {
	string s("What   a  great             weather  we have today"); 
	bool found ; 
	string::size_type pos ; 
	do { 
		found = false ; 
		cout << "string=" << s << endl ; 
		if ((pos = s.find("  ")) != string::npos) {
			found = true ; 
			cout << "Found 2 blanks at pos " << pos << endl ; 
			s.replace(pos, 2, " ") ; 
		}
		if ((pos = s.find("e")) != string::npos) { 
			found = true ; 
			cout << "string=" << s << endl ; 
			cout << "Found 1 e at pos " << pos << endl ; 
			s.replace(pos, 1, "") ; 
		}
	} while(found) ; 
	cout << "String is >" << s << "<" << endl ; 
    return 0;
}