C ++ uses the substr () function to remove leading and trailing Spaces

Recently I made a question and encountered the problem of removing spaces before and after the string. In Java, there seems to be a string function that is trim (), which can eliminate spaces after the string. For C ++, check that a C ++ standard library boost can be referenced, which can be easily solved, but you need to download and set the environment variables, so you have not done it. Of course, you can also use regular expressions for matching, but it seems that all of them are useless. It is better to use the substr () function, and the string has the find_last_not_of, find_first_not_of and other attributes, which is enough for us to solve the problem.

# Include <iostream>
# Include <vector>
# Include <string>
# Include <fstream>
Using namespace STD;
// Read each row from the file, and eliminate leading and trailing spaces to create a new string.
Int main ()
{
String newstring = "";

Vector <string> STR;
Ifstream fin ("a.txt ");
String line;
While (Getline (FIN, line ))
Str. push_back (line );

For (unsigned I = 0; I <Str. Size (); I ++)
{
Newstring + = STR [I]. substr (STR [I]. find_first_not_of (""), STR [I]. find_last_not_of ("")-str [I]. find_first_not_of ("") + 1 );
}
Cout <newstring <Endl;
Return 0;
}

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