Remove chars from the string

Question

To remove set of chars from a given string, i have implemented this function.

 void removeChars (string& str, const string& chars) { vector <bool> v (256, false); for (int i=0; i < chars.size(); ++i) { v[chars[i]] = true; } int k=0; for (int j=0; j < str.size(); ++j) { if (v[str[j]]==false) { str[k] = str[j]; ++k; } } str[k] = '\0'; }

But after processing the string from this function. Its printing some garbage value.

string s1 = "trying to remove chars from string"; string s2 = "tr"; removeChars2 (s1, s2);

Now print s1

ying o emove chas fom sing string Expected : ying o emove chas fom sing

is there anything wrong in this implementation.

What is the problem? I don't see any obvious "garbage values"? It helps a lot if you describe both the output you're getting and the output you expected — Stack Overflow is garbage
– Stack Overflow is garbage, Commented Dec 2, 2013 at 12:12
@DeveshAgrawal add str.erase(k); at the end of the RemoveChars function. — yasen
– yasen, Commented Dec 2, 2013 at 12:29

mcserep · Accepted Answer · 2013-12-02 12:17:23Z

Use STL algorithms, and you don't have to reimplement everything :)

string text("trying to remove chars from string"); char toRemove[] = "tr"; for (unsigned int i = 0; i < strlen(toRemove); ++i) text.erase(std::remove(text.begin(), text.end(), toRemove[i]), text.end()); std::cout << text << std::endl;

Some programmer dude · Accepted Answer · 2013-12-02 12:17:38Z

1

You should not add terminator character for std::string, it keeps track of the string end in other ways.

Instead of modifying str directly, I would recommend you append characters to a new string, and then copy that string to str when done.

answered Dec 2, 2013 at 12:17

Some programmer dude

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2 Comments

Devesh Agrawal Over a year ago

I appreciate the answer. But it was asked to modify the original string. No extra space is allowed.

Some programmer dude Over a year ago

@DeveshAgrawal Then you might be interested in the resize method of std::string.

Emmanuel · Accepted Answer · 2013-12-02 12:23:07Z

0

Use str.resize(k); instead of str[k] = '\0';

answered Dec 2, 2013 at 12:23

Emmanuel

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1 Comment

Devesh Agrawal Over a year ago

Its working fine with resize(k). my thought is it shouldn't be resize(k-1) ? because there is no char at kth place.

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