9.5.5

9.50
@Yue Wang

#include <iostream>
#include <string>
#include <vector>

auto sum_for_int(std::vector<std::string> const& v)
{
    int sum = 0;
    for (auto const& s : v)
        sum += std::stoi(s);
    return sum;
}

auto sum_for_float(std::vector<std::string> const& v)
{
    float sum = 0.0;
    for (auto const& s : v)
        sum += std::stof(s);
    return sum;
}

int main()
{
    std::vector<std::string> v = { "1", "2", "3", "4.5" };
    std::cout << sum_for_int(v) << std::endl;
    std::cout << sum_for_float(v) << std::endl;

    return 0;
}

9.51
@Soyn

#include <iostream>
#include <string>
#include <vector>
/*@Soyn
*Ex 9.51
*Date: 2015.6.12
*/
using namespace std;
class My_date{
private:
    unsigned year, month, day;
public:
    My_date(const string &s){

        unsigned tag;
        unsigned format;
        format = tag = 0;

        // 1/1/1900
        if(s.find_first_of("/")!= string :: npos)
        {
            format = 0x01;
        }

        // January 1, 1900 or Jan 1, 1900
        if((s.find_first_of(',') >= 4) && s.find_first_of(',')!= string :: npos){
            format = 0x10;
        }
        else{ // Jan 1 1900
            if(s.find_first_of(' ') >= 3
                && s.find_first_of(' ')!= string :: npos){
                format = 0x10;
                tag = 1;
            }
        }

        switch(format){

        case 0x01:
            day = stoi(s.substr(0, s.find_first_of("/")));
            month = stoi(s.substr(s.find_first_of("/") + 1, s.find_last_of("/")- s.find_first_of("/")));
            year = stoi(s.substr(s.find_last_of("/") + 1, 4));

        break;

        case 0x10:
            if( s.find("Jan") < s.size() )  month = 1;
            if( s.find("Feb") < s.size() )  month = 2;
            if( s.find("Mar") < s.size() )  month = 3;
            if( s.find("Apr") < s.size() )  month = 4;
            if( s.find("May") < s.size() )  month = 5;
            if( s.find("Jun") < s.size() )  month = 6;
            if( s.find("Jul") < s.size() )  month = 7;
            if( s.find("Aug") < s.size() )  month = 8;
            if( s.find("Sep") < s.size() )  month = 9;
            if( s.find("Oct") < s.size() )  month =10;
            if( s.find("Nov") < s.size() )  month =11;
            if( s.find("Dec") < s.size() )  month =12;

            char chr = ',';
            if(tag == 1){
                chr = ' ';
            }
            day = stoi(s.substr(s.find_first_of("123456789"), s.find_first_of(chr) - s.find_first_of("123456789")));

            year = stoi(s.substr(s.find_last_of(' ') + 1, 4));
            break;
        }
    }

    void print(){
        cout << "day:" << day << " " << "month: " << month << " " << "year: " << year;
    }
};
int main()
{
    My_date d("Jan 1 1900");
    d.print();
    return 0;
}