diff options
Diffstat (limited to 'src/corelib/doc/snippets/code/src_corelib_tools_qhash.cpp')
| -rw-r--r-- | src/corelib/doc/snippets/code/src_corelib_tools_qhash.cpp | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/src/corelib/doc/snippets/code/src_corelib_tools_qhash.cpp b/src/corelib/doc/snippets/code/src_corelib_tools_qhash.cpp index 43d64fc08e..0976488a48 100644 --- a/src/corelib/doc/snippets/code/src_corelib_tools_qhash.cpp +++ b/src/corelib/doc/snippets/code/src_corelib_tools_qhash.cpp @@ -220,7 +220,7 @@ for (i = hash.begin(); i != hash.end(); ++i) //! [19] QHash<QString, int>::iterator i = hash.begin(); while (i != hash.end()) { - if (i.key().startsWith("_")) + if (i.key().startsWith('_')) i = hash.erase(i); else ++i; @@ -233,7 +233,7 @@ QHash<QString, int>::iterator i = hash.begin(); while (i != hash.end()) { QHash<QString, int>::iterator prev = i; ++i; - if (prev.key().startsWith("_")) + if (prev.key().startsWith('_')) hash.erase(prev); } //! [20] @@ -242,7 +242,7 @@ while (i != hash.end()) { //! [21] // WRONG while (i != hash.end()) { - if (i.key().startsWith("_")) + if (i.key().startsWith('_')) hash.erase(i); ++i; } @@ -298,6 +298,25 @@ while (i != hash.end() && i.key() == "plenty") { } //! [26] +//! [27] +for (QHash<int, QString>::const_iterator it = hash.cbegin(), end = hash.cend(); it != end; ++it) { + cout << "The key: " << it.key() << endl + cout << "The value: " << it.value() << endl; + cout << "Also the value: " << (*it) << endl; +} +//! [27] + +//! [28] +// Inefficient, keys() is expensive +QList<int> keys = hash.keys(); +int numPrimes = std::count_if(keys.cbegin(), keys.cend(), isPrimeNumber); +qDeleteAll(hash2.keys()); + +// Efficient, no memory allocation needed +int numPrimes = std::count_if(hash.keyBegin(), hash.keyEnd(), isPrimeNumber); +qDeleteAll(hash2.keyBegin(), hash2.keyEnd()); +//! [28] + //! [qhashbits] inline uint qHash(const std::vector<int> &key, uint seed = 0) { |