int main(int argc, char *argv[]){ std::string date_string; std::cout<<"Enter the date in DD-MM-YYYY format."<<std::endl; std::cin>>date_string; int d=std::atoi(date_string.substr(0, 2).c_str()); int m=std::atoi(date_string.substr(3, 2).c_str()); int y=std::atoi(date_string.substr(6, 4).c_str()); int days_of_month[]={31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; if(m>12 || m<1){ std::cout<<"invalid"<<std::endl; }else{ int is_leap=(y%4==0) && ((y%100!=0) || (y%100==0 && y%400==0)); if(d<=(days_of_month[m-1]+(m==2? is_leap : 0))){ std::cout<<"The given date is valid."<<std::endl; }else{ std::cerr<<"The given date is *INVALID* !"<<std::endl; } }}/* Sample Run :rahul@kodersbox:~/Desktop$ g++ date_validation.cpp -o date_validationrahul@kodersbox:~/Desktop$ ./date_validationEnter the date in DD-MM-YYYY format.29-02-1000The given date is *INVALID* !*/