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A template allows us to write a function/class once and use it for different data types.
Why needed:
int, float, double, etc.Example idea: max(a,b) should work for int, float, double.
A function template is a generic function definition.
Basic syntax:
template <class T> or template <typename T>T func(T a, T b) { ... }When called with a specific type, compiler creates the real function.
T is a type parameter (placeholder).int, compiler instantiates a version for int.Important point: template code is generated at compile time.
Templates can be overloaded like normal functions. If a non-template function matches better, compiler may prefer it.
For Sem 1, keep idea simple: “Templates can be overloaded and compiler chooses best match.”
A class template is a generic class.
Example idea:
template<class T> class Box { T data; ... }When used as Box<int>, it becomes a class storing int.
Templates:
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A template allows us to write a function/class once and use it for different data types.
Why needed:
int, float, double, etc.Example idea: max(a,b) should work for int, float, double.
A function template is a generic function definition.
Basic syntax:
template <class T> or template <typename T>T func(T a, T b) { ... }When called with a specific type, compiler creates the real function.
T is a type parameter (placeholder).int, compiler instantiates a version for int.Important point: template code is generated at compile time.
Templates can be overloaded like normal functions. If a non-template function matches better, compiler may prefer it.
For Sem 1, keep idea simple: “Templates can be overloaded and compiler chooses best match.”
A class template is a generic class.
Example idea:
template<class T> class Box { T data; ... }When used as Box<int>, it becomes a class storing int.
Templates:
An exception is an abnormal situation that occurs during program execution (e.g., divide by zero, file open failure).
Exception handling is a mechanism to handle such errors gracefully without crashing the program.
This improves reliability and separates normal logic from error-handling logic.
Flow:
We can write multiple catch blocks for different exception types.
Catch-all:
catch(...) catches any type of exception.Order matters:
When an exception is thrown, C++ searches for a matching catch. If it moves out of functions, destructors for local objects are called automatically.
This process is called stack unwinding.
Common situations:
bad_alloc in advanced cases)In Sem 1, focus on understanding try/throw/catch and writing a small flow.
catch(...) before specific catch blocks.Normal code → try block
↓ exception occurs
throw exception → search matching catch → handle → continue/exit
catch(specific) → catch(less specific) → catch(...)
From this topic
Templates support generic programming by allowing the same function/class to work for different data types. Advantages (any three):
Hence templates are widely used in C++ libraries.
A function template is written using template<class T> and uses T as a placeholder type. When called with int/double, compiler generates the specific function (instantiation). Example idea: generic max(a,b).
A function template is a generic function definition that works for different data types.
Syntax:
template <class T> (or template <typename T>)T func(T a, T b) { ... }Working:
T acts as a type parameter.Advantage: reduces duplication and supports generic programming.