#include <iostream>
#include <string>
#include <algorithm>

int main()
{
    std::string str = "ab*+cd*+ef*+gh*+ij*+kl*+" ;
    std::cout << str << '\n'  ;

    constexpr char asterisk = '*' ;

    // erase first asterisk
    auto pos = str.find(asterisk) ;
    if( pos != std::string::npos ) str.erase(pos,1) ;
    std::cout << str << '\n'  ;

    // erase last asterisk
    pos = str.rfind(asterisk) ;
    if( pos != std::string::npos ) str.erase(pos,1) ;
    std::cout << str << '\n'  ;

    // erase all asterisk
    while( ( pos = str.find(asterisk) ) != std::string::npos ) str.erase(pos,1) ;
    std::cout << str << '\n'  ;

    // erase all '+'
    str.erase( std::remove( str.begin(), str.end(), '+' ), str.end() ) ;
    std::cout << str << '\n'  ;
}