Why did I get error by using strchr() in C++?

Question

#include <iostream>
#include <string>
#include <cstring>
using namespace std;

int main(){
    string a="asdasd";
    if(!strchr(a,'a')) cout<<"yes";
    return 0;
}

I just began to learn C++ programming and I don't know why I got error in this line

if(!strchr(a,'a')) cout<<"yes";

But if I tried to code it like this, it would run very well.

if(!strchr("asdasd",'a')) cout<<"yes";

I know it is a stupid question but I really don't know why.. sorry..

You should always show us the *exact* error you get. Also, you should stop mucking about with C-style strings and their related functions in a C++ program. — Jesper Juhl, Aug 01 '16 at 15:34
Oh!! Thank you guys, because I saw others use strchr so I thought it also worked for C++. — user299560, Aug 01 '16 at 15:49
`strchr` _can_ be used in C++ but it's not idiomatic and typically frowned upon. In C++ there are much better ways of dealing with strings as you are now finding out. — Captain Obvlious, Aug 01 '16 at 16:40

score 3 · Accepted Answer · answered Aug 01 '16 at 15:32

3

The library function strchr is for use with C-style strings, not the C++ string type.

answered Aug 01 '16 at 15:32

Thomas Padron-McCarthy

27,232
8
51
75

Thank you so much!!! Sorry for my stupid question again.. – user299560 Aug 01 '16 at 15:49

score 2 · Answer 2 · answered Aug 01 '16 at 16:27

2

When using std::string, the closest equivalent of strchr is find:

#include <iostream>
#include <string>

int main(){
    std::string a="asdasd";
    if(a.find('a') != std::string::npos) std::cout<<"yes";
}

answered Aug 01 '16 at 16:27

Jerry Coffin

476,176
80
629
1,111

Why did I get error by using strchr() in C++?

2 Answers2