Today's error series: the usage of the rfind() function of string in C++

Today’s tips to consolidate records:

A one-sentence summary of rfind() function usage: Find the first occurrence of a character or substring from back to front.

The find() function searches from front to back.

Give a chestnut: rfind()

	string path = "012/456789/2021-01-18";  //待操作的字符串
	int pos = path.rfind('/'); // rfind()，从后向前找到'/'第一次出现的位置
	cout << "pos is :" << pos << endl; // 打印‘/’的位置
	if (pos != string::npos)
	{
    
    
		string path_2 = path.substr(pos + 1); // 从下一个位置开始截取
		cout << path_2.c_str() << endl; // 打印日期
	}

Output:

pos is :10
2021-01-18

Explain that the character'/' last appeared in the tenth position of the string "012/456789/2021-01-18", and print all the strings after the last'/'.

Pay attention to the top and bottom contrast

Give another chestnut: find()

	string path = "012/456789/2021-01-18";
	int pos = path.find('/'); // find()，从前向后找到'/'的位置
	cout << "pos is :" << pos << endl; // 打印‘/’的位置
	if (pos != string::npos)
	{
    
    
		string path_2 = path.substr(pos + 1); // 从下一个位置开始截取
		cout << path_2.c_str() << endl; // 打印日期
	}

Output:

pos is :3
456789/2021-01-18

Explain that the character'/' appears in the 3rd position of the string "012/456789/2021-01-18" for the first time, and all the strings after the first'/' are printed.

End:

Sharing is also a way to deepen your understanding of the problem again. It may not be comprehensive, but it is definitely useful and will continue to be improved later~