#include <iostream>
#include <algorithm>
#include <cstring>
 
int main()
{
    char input[] = "Some input   with \t multiple \n spaces";
 
    std::cout << "Length of string before: " << std::strlen(input) << '\n';
    std::cout << "input before: \"" << input << "\"\n";
 
    auto last = std::unique(&input[0], input + std::strlen(input), [](char const& a, char const &b)
    {
        return std::isspace(a) && std::isspace(b);
    });
    *last = '\0';  // Terminate string
 
    std::cout << "Length of string after: " << std::strlen(input) << '\n';
    std::cout << "last - input: " << (last - input) << '\n';
    std::cout << "input after: \"" << input << "\"\n";
}
 

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