#include<bits/stdc++.h>
using namespace std;
int main(){
int length;
cin>>length;
string s(length,'\0');
cin>>s;
cout<<s;
}
int the code above firstly im taking a int length and then using it to define the size of the string but the issue is that when i cin>>s after defining length the string still takes more char's than length
i.e OUTPUT->
3
Hello
Hello
this should not happen after defining length of the string,
Maybe you want:
std::string s(length, '\0');
std::cin.get(s.data(), s.size());
s.c_str() returns a pointer to const data, so you can't fill the string using that pointer. Use s.data() (C++17 and later) or &s[0] to get a pointer to writable memory. Otherwise, use a std::vector<char> instead, and then copy it to a std::string afterwards.The documentation says:
istream& operator>> (istream& is, string& str);Extract string from stream
Extracts a string from the input stream
is, storing the sequence instr, which is overwritten (the previous value ofstris replaced). Each extracted character is appended to the string as if its memberpush_backwas called.
So, when you're doing:
cin>>s;
the contents of the string are being replaced with your input that can be of any size because characters are being appended to the string as if push_back was called.
Short answer: yes, it should. You misintepret meaning of instructions you give, without regard to documentation.
Long answer: You had created an empty string with reservation of 3 chars. operator>> assigned new value to s. Old value, a 3-character capable string is lost.
