C++/String/string subscript indexer — различия между версиями
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Версия 14:21, 25 мая 2010
Содержание
Accessing characters in a string
#include <iostream>
#include <string>
#include <cctype>
using std::cout;
using std::cin;
using std::endl;
using std::string;
int main() {
string text = "asdffdsaasdf";
int vowels = 0;
int consonants = 0;
for(int i = 0 ; i < text.length() ; i++)
if(std::isalpha(text[i]))
switch(std::tolower(text[i])) {
case "a": case "e": case "i":
case "o": case "u":
vowels++;
break;
default:
consonants++;
}
cout << "Your input contained "
<< vowels << " vowels and "
<< consonants << " consonants."
<< endl;
return 0;
}
/*
Your input contained 3 vowels and 9 consonants.
*/
Modify char in a string by indexer
#include <iostream>
using std::cout;
using std::endl;
#include <string>
using std::string;
int main()
{
string string1( "cat" );
string string2;
string string3;
string2 = string1;
string3.assign( string1 );
cout << "string1: " << string1 << "\nstring2: " << string2
<< "\nstring3: " << string3 << "\n\n";
string2[ 0 ] = string3[ 2 ] = "r";
cout << "string1: " << string1 << "\nstring2: " << string2 << "\nstring3: ";
return 0;
}
/*
string1: cat
string2: cat
string3: cat
string1: cat
string2: rat
string3:
*/
switch statement based on char value
#include <iostream>
#include <string>
#include <cctype>
using std::cout;
using std::cin;
using std::endl;
using std::string;
int main() {
string text = "asdffdsaasdf";
int vowels = 0;
int consonants = 0;
for(int i = 0 ; i < text.length() ; i++)
if(std::isalpha(text[i]))
switch(std::tolower(text[i])) {
case "a": case "e": case "i":
case "o": case "u":
vowels++;
break;
default:
consonants++;
}
cout << "Your input contained "
<< vowels << " vowels and "
<< consonants << " consonants."
<< endl;
return 0;
}
/*
Your input contained 3 vowels and 9 consonants.
*/
Tests whether a string is a palindrome
#include <iostream>
#include <string>
#include <vector>
using namespace std;
bool is_palindrome(string s)
{
if (s.length() <= 1)
return true;
char first = s[0];
char last = s[s.length() - 1];
if (first == last){
string subString = s.substr(1, s.length() - 2);
return is_palindrome(subString);
}
else
return false;
}
int main()
{
cout << "Enter a string: ";
string input;
getline(cin, input);
if (!is_palindrome(input))
cout << "false";
return 0;
}