Scoped Initialization in Conditional Blocks

Snippet

Scoped Initialization in Conditional Blocks

Introduced in C++17, the 'if' statement with an initializer allows you to declare and initialize a variable whose scope is limited strictly to the 'if' and 'else' branches. This prevents variable leakage into the surrounding scope, improving code safety and readability.

snippet.cpp

cpp

#include <iostream>
#include <map>
 
int main() {
    std::map<std::string, int> scores = {{"Alice", 10}, {"Bob", 20}};
 
    // C++17 'if' with initializer: 'it' is only visible inside this block
    if (auto it = scores.find("Alice"); it != scores.end()) {
        std::cout << "Found: " << it->second << std::endl;
    } else {
        std::cout << "Not found" << std::endl;
    }
 
    return 0;
}

Breakdown

if (auto it = scores.find("Alice"); it != scores.end())

Declares 'it' and checks the condition in a single line. 'it' only exists within this 'if/else'.

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Scoped Initialization in Conditional Blocks

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