Please tell me what the single colon is used for in these examples.

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Please tell me what the single colon is used for in these 2 examples.
Example 1:

Super(const std::string& str) : mStr(str) {}

Example 2:

Sub(int i) : Super(""), mInt(i) {}

What I have tried:

Please tell me what the single colon is used for in these 2 examples.
Example 1:

Super(const std::string& str) : mStr(str) {}

Example 2:

Sub(int i) : Super(""), mInt(i) {}

Posted 10-Dec-18 15:31pm

Member 13010616

Updated 10-Dec-18 22:31pm

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KarstenK 11-Dec-18 2:27am

it standard language syntax. Read the documentations.

2 solutions

Solution 2

Please study C++ Language Reference | Microsoft Docs[^] you will learn much faster than by posting basic questions here.

Posted 10-Dec-18 22:31pm

Richard MacCutchan

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Rick York · Accepted Answer · 2018-12-10T16:12:00

It is separating the derived class constructor from the base class constructor and from member initializations. The general format is :

C++

DerivedClass( derived_args, base_arguments )
    : BaseClass( base_arguments )
    , m_Member1( initial_value1 )
    , m_Member2( initial_value2 )
{
   // constructor implementation
}

I recommend reading this tutorial at the C++ reference site: Classes (I) - C++ Tutorials[^]