Remove extra white spaces in C++

Question

I tried to write a script that removes extra white spaces but I didn\'t manage to finish it.

Basically I want to transform abc sssd g g sdg gg gf into

Answer 1

for in-place modification you can apply erase-remove technic:

#include 
#include 
#include 
#include 

int main()
{
    std::string input {"asfa sas    f f dgdgd  dg   ggg"};
    bool prev_is_space = true;
    input.erase(std::remove_if(input.begin(), input.end(), [&prev_is_space](unsigned char curr) {
        bool r = std::isspace(curr) && prev_is_space;
        prev_is_space = std::isspace(curr);
        return r;

    }), input.end());

    std::cout << input << "\n";
}

So you first move all extra spaces to the end of the string and then truncate it.

---

The great advantage of C++ is that is universal enough to port your code to plain-c-static strings with only few modifications:

void erase(char * p) {
    // note that this ony works good when initial array is allocated in the static array
    // so we do not need to rearrange memory
    *p = 0; 
}

int main()
{
    char input [] {"asfa sas    f f dgdgd  dg   ggg"};
    bool prev_is_space = true;
    erase(std::remove_if(std::begin(input), std::end(input), [&prev_is_space](unsigned char curr) {
        bool r = std::isspace(curr) && prev_is_space;
        prev_is_space = std::isspace(curr);
        return r;

    }));

    std::cout << input << "\n";
}

Interesting enough remove step here is string-representation independent. It will work with std::string without modifications at all.