How to use the String class in C++

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String Typ

Flipping through the books and reading all kinds of articles, I feel that there is nothing to say about String, so let's go over it briefly for a while.

1. The string in C++ is different from the string in C

There is no concept of string in C language, it is actually an array of characters, but there is a header file "string.h" in C, which provides function interfaces such as string concatenation, copy, comparison and so on. String in C++ is a string class, so you need to include the string header file when using it. Since string is a class under the std namespace, you also need to introduce the std namespace. Here is the sample code:

# include using std::string

2. Definition and initialization of string object in C++.

The string class in C++ provides several ways to initialize a string object:

String str1; / / default initialization, str1 is an empty string string str2 (str1); / / initialize string str21 = str1;string str2 = ("HelloWorld!") with a known string using the copy constructor; string str3 ("HelloWorld")

3. The operator of C++ string object (take the string s as an example)

Os > s / / write the input stream to s getline (is S) / / read a line from is to s.empty () / / determine whether the string s is empty s.size () / / get the size of the string s = = S2 / / compare whether the string S1 is equal to the string s2s1 + S2 / / concatenate the strings S1 and S2 into a new amount string

Read input from the command line and save to a string:

# include int main () {std::string line; while (getline (cin, line)) if (line.size () > 1024) cout