cpp

Designing Callbacks in C++

Callback is a function that we pass to another APIs as argument while calling them. 

function pointer callback as an argument is as follows,

C++

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std::string buildCompleteMessage(std::string rawData, std::string (* encrypterFunPtr)(std::string) ) std::string buildCompleteMessage(std::string rawData, std::string (* encrypterFunPtr)(std::string) ) {     // Add some header and footer to data to make it complete message     rawData = "[HEADER]" + rawData + "[FooTER]";       // Call the callBack provided i.e. function pointer to encrypt the     rawData = encrypterFunPtr(rawData);       return rawData; }

Find & Replace all sub strings – using STL

#include <iostream>

#include <string>

 

void findAndReplaceAll(std::string & data, std::string toSearch, std::string replaceStr)

{

// Get the first occurrence

size_t pos = data.find(toSearch);

 

// Repeat till end is reached

while( pos != std::string::npos)

{

// Replace this occurrence of Sub String

data.replace(pos, toSearch.size(), replaceStr);

// Get the next occurrence from the current position

pos =data.find(toSearch, pos + toSearch.size());

}

}

 

int main()

{

std::string data = "Boost Library is simple C++ Library";

 

std::cout<<data<<std::endl;

 

findAndReplaceAll(data, "Lib", "XXX");

 

std::cout<<data<<std::endl;

 

 

return 0;

}