Question

How to sort a vector of strings where each string represents a decimal number in C++

Answer 1

#include <iostream>
#include <vector>
#include <string>
#include <algorithm> // For std::sort

// Comparator function to sort strings as decimal numbers
bool compareAsDecimal(const std::string& a, const std::string& b) {
    // Convert strings to double for comparison
    double numA = std::strtod(a.c_str(), nullptr);
    double numB = std::strtod(b.c_str(), nullptr);
    
    return numA < numB;
}

int main() {
    // Input array of strings
    std::vector<std::string> numbers = {"12.3", "5.6", "789.1", "3.14", "456.0", "0", "0.01", "4.0"};

    // Sort the array using the custom comparator
    std::sort(numbers.begin(), numbers.end(), compareAsDecimal);

    std::cout << "Sorted array of decimal strings:" << std::endl;
    for (const std::string& num : numbers) {
        std::cout << num << "  ";
    }
}



/*
run:
    
Sorted array of decimal strings:
0  0.01  3.14  4.0  5.6  12.3  456.0  789.1  
    
*/

 

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