CODEWITHSUNDEEP
c++qt
vicatcu
vicatcu

Reputation: 5837

Qt String Comparison

Suppose I have:

QString x;

Is the following code fragment:

if(x.compare("abcdefg") == 0){
  doSomething();
}
else{
  doSomethingElse();
}

... functionally equivalent to:

if(x == "abcdefg"){
  doSomething();
}
else{
  doSomethingElse();
}

I could prove this for myself by writing a fairly trivial program and executing it, but I was surprised I couldn't find the question / answer here, so I thought I'd ask it for the sake of future me / others.

Upvotes: 0

Views: 10429

Answers (1)

NathanOliver
NathanOliver

Reputation: 180650

QString::compare will only return zero if the string passed to it and the string it is called on are equal.

Qstring::operator== returns true if the strings are equal otherwise, false.

Since compare only returns zero when the strings are equal then

(qstrign_variable.compare("text") == 0) == (qstrign_variable == "text")

If qstrign_variable contains "text" in the above example. If qstrign_variable contains something else then both cases evaluate to false.

Also note that std::string has the same behavior

Upvotes: 3

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