find

語法:

    #include <string>
    size_type find( const string& str, size_type index = 0 ) const;
    size_type find( const charT* str, size_type index = 0 ) const;
    size_type find( const charT* str, size_type index, size_type length ) const;
    size_type find( charT ch, size_type index = 0 ) const;

find 方法返回下列值中的一個:

1. 當前字元串中 str 第一次出現的位置，以 index 開始，若未找到，返回 string::npos
2. the first length characters of str within the current string, starting at index, or string::npos if nothing is found.

For example:

	string str1( "Alpha Beta Gamma Delta" );
	string::size_type loc1 = str1.find( "Omega", 0 );
	string::size_type loc2 = str1.find( "Gamma", 0 );
	if( loc1 != string::npos ) {
		cout << "Found Omega at " << loc1 << endl;
	} else {
		cout << "Didn't find Omega" << endl;
	}
	if( loc2 != string::npos ) {
		cout << "Found Gamma at " << loc2 << endl;
	} else {
		cout << "Didn't find Gamma" << endl;
	}

The result is

Didn't find Omega
Found Gamma at 11

Related Topics: find_first_not_of, find_first_of, find_last_not_of, find_last_of, rfind