STL Map Problem

[Mike Copeland]

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

 

[Victor Bazarov]

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

 

[Ian Collins]

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

When you ask about an error, post it!

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

Why are you trying to assign a bool (the result of !=) to an iterator?

 

[terminator]

are familiar with basics of c++?
you need to read some text books 1st.
then design your algorithm.