使用StringStream查找两个日期之间的天数

给定两个表示两个日期的字符串str1和str2 ，任务是计算给定两个日期之间的天数。鉴于给出的日期是1971年以后。

例子：

Input: str1 = “2020-01-29”, str2 = “2020-01-30”
Output: 1
Explanation:
The number of days between 29^th January and 30^th January is 1.

Input: str1 = “1971-06-29”, str2 = “2019-06-23”
Output: 17526

方法：想法是将两个日期都转换成各自的秒数。由于一天中有86，400秒，因此两天之间的天数可以通过将秒数之差除以86，400来得出。

下面是上述方法的实现：

// C++ implementation of the above approach
#include 
#include 
#include 
using namespace std;
  
// Function to find the number of days
// between given two dates
int daysBetweenDates(string date1, string date2)
{
    stringstream ss(date1 + "-" + date2);
    int year, month, day;
    char hyphen;
  
    // Parse the first date into seconds
    ss >> year >> hyphen >> month >> hyphen >> day;
    struct tm starttm = { 0, 0, 0, day,
                          month - 1, year - 1900 };
    time_t start = mktime(&starttm);
  
    // Parse the second date into seconds
    ss >> hyphen >> year >> hyphen
        >> month >> hyphen >> day;
    struct tm endtm = { 0, 0, 0, day,
                        month - 1, year - 1900 };
    time_t end = mktime(&endtm);
  
    // Find out the difference and divide it
    // by 86400 to get the number of days
    return abs(end - start) / 86400;
}
  
// Driver code
int main()
{
    string str1 = "2019-09-12";
    string str2 = "2020-08-04";
    cout << daysBetweenDates(str1, str2);
    return 0;
}

输出：

327