Re: STL Map Problem

From:

Victor Bazarov <v.bazarov@comcast.invalid>

Newsgroups:

comp.lang.c++

Date:

Sat, 30 Mar 2013 20:20:05 -0400

Message-ID:

<kj7vc0$6n7$1@dont-email.me>

On 3/30/2013 6:24 PM, Mike Copeland wrote:

    I am developing a small (and seemingly simple) STL map application,
yet I can't get a clean compile. Below is code that produces a compiler
error on the "find" call, where the compiler doesn't accept the
assignment operator for the iterator. Please advise. TIA

    map<string, int> convMap;
    map<string, int>::iterator kIter;
    string str = "Oops";
    convMap[str] = 17;
    kIter = convMap.find(str) != convMap.end(); // <== error!

You're trying to assign the boolean to the iterator. Why? Your
expression is evaluated this way:

kIter = (convMap.find(str) != convMap.end())

(since the inequality operator has precedence over assignment). Did you
mean to assign first, like

(kIter = convMap.find(str))

and then compare it? Why compare it if you aren't going to use the
result of the comparison? Could it be that you need to remove
everything starting with "!=" and until the semicolon (excluding it)?

    if(kIter != convMap.end())
    {
       int ppp = kIter->second;
    }
    else // not found

V
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