Explain the purpose of the pubspec.lock file in Dart and Flutter projects.

The pubspec.lock file in Dart and Flutter projects is used to lock specific versions of dependencies used in the project.

When you specify dependencies in pubspec.yaml, you usually define version ranges. During the first package installation, the flutter pub get or dart pub get command selects specific versions that satisfy these ranges and records them in pubspec.lock.

Purpose of pubspec.lock:

• To ensure that all developers and CI servers use the same package versions, ensuring stability and reproducibility of builds.
• To avoid unexpected issues related to dependency updates.

If pubspec.lock is deleted and pub get is run, newer versions of packages may be installed, which can sometimes lead to incompatibilities.