String into integer in C++ -

i have string value : 2014-04-14

i want convert integer 20140414

i know string in integer can done

std::string mystring = "45"; int value = atoi(mystring.c_str()); //value = 45 

but don't know how remove - sign.

using streams:

std::istringstream iss("2014-04-14"); 

then if have c++11, can use new get_time io manipulator:

std::tm tm; if (iss >> get_time(&tm, "%y-%m-%d"))     ... 

the std::tm structure has extracted values, namely:

• years since 1900 stored in tm.tm_year
• months since january (so 0..11) stored in tm.tm_mon
• day of month (1..31) stored in tm.tm_mday

so, desired value is:

int value = (tm.tm_year + 1900) * 10000 + (tm.tm_mon + 1) * 100 + tm.tm_mday; 

---

alternatively, or c++03, can parse values out of istringstream yourself:

int year, month, day; char c; if (iss >> year >> c && c == '-' &&     iss >> month >> c && c == '-' &&     iss >> day) {     int value = year * 10000 + month * 100 + day;     ... use value ... } else     std::cerr << "invalid date\n";