C++ Tutorial/string/string char array — различия между версиями
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Версия 14:21, 25 мая 2010
Содержание
Convert string to C-Style string
#include <iostream>
using std::cout;
using std::endl;
#include <string>
using std::string;
int main()
{
string string1( "STRINGS" );
cout << "string string1 is " << string1
<< "\nstring1 converted to a C-Style string is "
<< string1.c_str() << "\n";
return 0;
}string string1 is STRINGS string1 converted to a C-Style string is STRINGS
Delete characters from the string given position and count
#include <string>
#include <algorithm>
#include <iostream>
using namespace std;
int main ()
{
string strSample ("Hello String! Wake up to a beautiful day!");
strSample.erase (13, 28);
cout << strSample;
return 0;
}If character found, "erase" to deletes a character
#include <string>
#include <algorithm>
#include <iostream>
using namespace std;
int main ()
{
string strSample ("Hello String!");
// Find a character "S" in the string using STL find algorithm
string::iterator iCharS = find ( strSample.begin (), strSample.end (), "S");
// If character found, "erase" to deletes a character
cout << "Erasing character "S" from the sample string:" << endl;
if (iCharS != strSample.end ())
strSample.erase (iCharS);
cout << strSample;
return 0;
}Insert character to the end of a string
#include <string>
#include <iostream>
using namespace std;
int main(int argc, char** argv)
{
string str1;
str1.insert(str1.end(), "h");
str1.insert(str1.end(), "e");
str1.insert(str1.end(), "l");
str1.insert(str1.end(), "l");
str1.insert(str1.end(), "o");
for (string::const_iterator it = str1.begin(); it != str1.end(); ++it) {
cout << *it;
}
cout << endl;
return (0);
}Locating all instances of a character
#include <string>
#include <iostream>
using namespace std;
int main ()
{
string strSample ("Good day String!");
// Find substring "day" in it...
size_t nOffset = strSample.find ("day", 0);
cout << "Locating all instances of character "a"" << endl;
const char chCharToSearch = "a";
size_t nCharacterOffset = strSample.find (chCharToSearch, 0);
while (nCharacterOffset != string::npos)
{
cout << """ << chCharToSearch << "" found";
cout << " at position: " << nCharacterOffset << endl;
// Make the "find" function search forward from the next character onwards
size_t nCharSearchOffset = nCharacterOffset + 1;
nCharacterOffset = strSample.find(chCharToSearch,nCharSearchOffset);
}
return 0;
}String array
#include <iostream>
#include <string>
using namespace std;
int main()
{
string sentence, words[10];
int pos = 0, old_pos = 0, nwords, i = 0;
sentence = "Eskimos have 23 ways to ";
sentence += "describe snow";
while (pos < sentence.size()) {
pos = sentence.find(" ", old_pos);
words[i++].assign(sentence, old_pos, pos - old_pos);
cout << words[i - 1] << endl; //print words
old_pos = pos + 1;
}
nwords = i;
sentence = "C++ programmers ";
for (i = 1; i < nwords -1; ++i)
sentence += words[i] + " ";
sentence += "windows";
cout << sentence << endl;
}Use push_back() to add characters to a string
#include <iostream>
#include <string>
using namespace std;
int main()
{
string str1("A");
string str2("B");
string str3("G");
string str4;
cout << " str1: " << str1 << endl;
cout << " str2: " << str2 << endl;
cout << " str3: " << str3 << "\n\n";
// Use push_back() to add characters to str4.
for(char ch = "A"; ch <= "Z"; ++ch)
str4.push_back(ch);
cout << "str4 after calls to push_back(): " << str4 << endl;
cout << "Size and capacity of str4 is now " << str4.size() << " " << str4.capacity() << "\n\n";
return 0;
}