CODEWITHSUNDEEP
c++
naman singhal
naman singhal

Reputation: 1

why erase function is giving error in string function?

The erase function is giving an error of invalid arguments but I have passed

1st argument = index no.
2nd argument = no. of characters

then also it is giving error. Eg

word3 = word2.erase(word.begin(), word.length()/2-1);

Upvotes: 0

Views: 562

Answers (2)

Vlad from Moscow
Vlad from Moscow

Reputation: 310940

Member function begin() of class std::string returns iterator. That is its return type either std::string::iterator or std::string::const_iterator.

You are trying to use member function erase that has parameters of type std::string::size_type:

basic_string& erase(size_type pos = 0, size_type n = npos);

If you want to use this member function you should write the call like

word2.erase( 0, word.length()/2 - 1 )

If you want to use the function that uses iterators that is the following member function

iterator erase(const_iterator first, const_iterator last);

then the call can look like

word2.erase( word.begin(), std::next( word.begin(), word.length()/2 - 1 ) )

or simply

word2.erase( word.begin(), word.begin() + word.length()/2 - 1 )

I hope that is not a typo that you call the function for object with name word2 and in the expression used as the argument you use object with name word

Upvotes: 0

vsoftco
vsoftco

Reputation: 56547

Looking at http://en.cppreference.com/w/cpp/string/basic_string/erase (1) you see that you need to pass the index of the first character to erase and the number of how many characters to erase. You pass an iterator instead as the first argument. Just do

word3 = word2.erase(0, word.length()/2 -1);
//                     ^^^^
//                     this should probably be word2

or use the (3) overload that accepts a range:

word3 = word2.erase(word2.begin(), std::next(word2.begin(), word2.length()/2 -1));

I also believe you should have word2 inside your erase, not word.

Upvotes: 2

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