Cin je objekt, ktorý sa používa na prijímanie vstupu od používateľa, ale neumožňuje prijímať vstup vo viacerých riadkoch. Na akceptovanie viacerých riadkov používame funkciu getline(). Je to preddefinovaná funkcia definovaná v a hlavičkový súbor, ktorý sa používa na prijatie riadku alebo reťazca zo vstupného toku, kým nenájdete oddeľovací znak.
Syntax funkcie getline():
Existujú dva spôsoby reprezentácie funkcie:
- Prvým spôsobom deklarácie je odovzdanie troch parametrov.
istream& getline( istream& is, string& str, char delim );
Vyššie uvedená syntax obsahuje tri parametre, napr. je, str , a zdieľam .
Kde,
je: Je to objekt triedy istream, ktorý definuje, odkiaľ sa má čítať vstupný tok.
str: Je to reťazcový objekt, v ktorom je reťazec uložený.
scan.nextstring javazdieľam: Je to vymedzujúci znak.
Návratová hodnota
Táto funkcia vráti objekt vstupného toku, ktorý sa odovzdá funkcii ako parameter.
- Druhým spôsobom deklarácie je odovzdanie dvoch parametrov.
istream& getline( istream& is, string& str );
Vyššie uvedená syntax obsahuje dva parametre, napr. je a str . Táto syntax je takmer podobná vyššie uvedenej syntaxi; rozdiel je len v tom, že nemá žiadny vymedzujúci charakter.
tostring metóda java
Kde,
je: Je to objekt triedy istream, ktorý definuje, odkiaľ sa má čítať vstupný tok.
str: Je to reťazcový objekt, v ktorom je reťazec uložený.
Návratová hodnota
Táto funkcia tiež vracia vstupný tok, ktorý sa odovzdá funkcii ako parameter.
Poďme to pochopiť na príklade.
Najprv sa pozrieme na príklad, kde vezmeme vstup používateľa bez použitia funkcie getline().
#include #include using namespace std; int main() { string name; // variable declaration std::cout << 'Enter your name :' <>name; cout<<'
hello '<<name; return 0; } < pre> <p>In the above code, we take the user input by using the statement <strong>cin>>name,</strong> i.e., we have not used the <strong>getline()</strong> function.</p> <p> <strong>Output</strong> </p> <pre> Enter your name : John Miller Hello John </pre> <p>In the above output, we gave the name 'John Miller' as user input, but only 'John' was displayed. Therefore, we conclude that cin does not consider the character when the space character is encountered.</p> <p> <strong>Let's resolve the above problem by using getline() function.</strong> </p> <pre> #include #include using namespace std; int main() { string name; // variable declaration. std::cout << 'Enter your name :' << std::endl; getline(cin,name); // implementing a getline() function cout<<'
hello '<<name; return 0;} < pre> <p>In the above code, we have used the <strong>getline()</strong> function to accept the character even when the space character is encountered.</p> <p> <strong>Output</strong> </p> <pre> Enter your name : John Miller Hello John Miller </pre> <p>In the above output, we can observe that both the words, i.e., John and Miller, are displayed, which means that the getline() function considers the character after the space character also.</p> <p> <strong>When we do not want to read the character after space then we use the following code:</strong> </p> <pre> #include #include using namespace std; int main() { string profile; // variable declaration std::cout << 'Enter your profile :' << std::endl; getline(cin,profile,' '); // implementing getline() function with a delimiting character. cout<<'
profile is :'<<p>In the above code, we take the user input by using getline() function, but this time we also add the delimiting character('') in a third parameter. Here, delimiting character is a space character, means the character that appears after space will not be considered.<p></p> <p> <strong>Output</strong> </p> <pre> Enter your profile : Software Developer Profile is: Software </pre> <h3>Getline Character Array</h3> <p>We can also define the getline() function for character array, but its syntax is different from the previous one.</p> <p> <strong>Syntax</strong> </p> <pre> istream& getline(char* , int size); </pre> <p>In the above syntax, there are two parameters; one is <strong>char</strong> *, and the other is <strong>size</strong> .</p> <p> <strong>Where,</strong> </p> <p> <strong>char*:</strong> It is a character pointer that points to the array.</p> <p> <strong>Size:</strong> It acts as a delimiter that defines the size of the array means input cannot cross this size.</p> <p> <strong>Let's understand through an example.</strong> </p> <pre> #include #include using namespace std; int main() { char fruits[50]; // array declaration cout<< 'Enter your favorite fruit: '; cin.getline(fruits, 50); // implementing getline() function std::cout << '
Your favorite fruit is :'<<fruits << std::endl; return 0; } < pre> <p> <strong>Output</strong> </p> <pre> Enter your favorite fruit: Watermelon Your favorite fruit is: Watermelon </pre> <hr></fruits></pre></'
profile></pre></'
hello></pre></'
hello> Vo vyššie uvedenom výstupe sme zadali meno „John Miller“ ako vstup používateľa, ale zobrazilo sa iba „John“. Preto sme dospeli k záveru, že cin neberie do úvahy znak, keď sa stretne s medzerovým znakom.
Vyriešme vyššie uvedený problém pomocou funkcie getline().
#include #include using namespace std; int main() { string name; // variable declaration. std::cout << 'Enter your name :' << std::endl; getline(cin,name); // implementing a getline() function cout<<\'
hello \'<<name; return 0;} < pre> <p>In the above code, we have used the <strong>getline()</strong> function to accept the character even when the space character is encountered.</p> <p> <strong>Output</strong> </p> <pre> Enter your name : John Miller Hello John Miller </pre> <p>In the above output, we can observe that both the words, i.e., John and Miller, are displayed, which means that the getline() function considers the character after the space character also.</p> <p> <strong>When we do not want to read the character after space then we use the following code:</strong> </p> <pre> #include #include using namespace std; int main() { string profile; // variable declaration std::cout << 'Enter your profile :' << std::endl; getline(cin,profile,' '); // implementing getline() function with a delimiting character. cout<<\'
profile is :\'<<p>In the above code, we take the user input by using getline() function, but this time we also add the delimiting character('') in a third parameter. Here, delimiting character is a space character, means the character that appears after space will not be considered.<p></p> <p> <strong>Output</strong> </p> <pre> Enter your profile : Software Developer Profile is: Software </pre> <h3>Getline Character Array</h3> <p>We can also define the getline() function for character array, but its syntax is different from the previous one.</p> <p> <strong>Syntax</strong> </p> <pre> istream& getline(char* , int size); </pre> <p>In the above syntax, there are two parameters; one is <strong>char</strong> *, and the other is <strong>size</strong> .</p> <p> <strong>Where,</strong> </p> <p> <strong>char*:</strong> It is a character pointer that points to the array.</p> <p> <strong>Size:</strong> It acts as a delimiter that defines the size of the array means input cannot cross this size.</p> <p> <strong>Let's understand through an example.</strong> </p> <pre> #include #include using namespace std; int main() { char fruits[50]; // array declaration cout<< 'Enter your favorite fruit: '; cin.getline(fruits, 50); // implementing getline() function std::cout << '
Your favorite fruit is :'<<fruits << std::endl; return 0; } < pre> <p> <strong>Output</strong> </p> <pre> Enter your favorite fruit: Watermelon Your favorite fruit is: Watermelon </pre> <hr></fruits></pre></\'
profile></pre></\'
hello> Vo vyššie uvedenom výstupe môžeme pozorovať, že sú zobrazené obe slová, t.j. John a Miller, čo znamená, že funkcia getline() zohľadňuje aj znak za znakom medzery.
pd.merge
Ak nechceme čítať znak po medzere, použijeme nasledujúci kód:
#include #include using namespace std; int main() { string profile; // variable declaration std::cout << 'Enter your profile :' << std::endl; getline(cin,profile,' '); // implementing getline() function with a delimiting character. cout<<\'
profile is :\'<<p>In the above code, we take the user input by using getline() function, but this time we also add the delimiting character('') in a third parameter. Here, delimiting character is a space character, means the character that appears after space will not be considered.<p></p> <p> <strong>Output</strong> </p> <pre> Enter your profile : Software Developer Profile is: Software </pre> <h3>Getline Character Array</h3> <p>We can also define the getline() function for character array, but its syntax is different from the previous one.</p> <p> <strong>Syntax</strong> </p> <pre> istream& getline(char* , int size); </pre> <p>In the above syntax, there are two parameters; one is <strong>char</strong> *, and the other is <strong>size</strong> .</p> <p> <strong>Where,</strong> </p> <p> <strong>char*:</strong> It is a character pointer that points to the array.</p> <p> <strong>Size:</strong> It acts as a delimiter that defines the size of the array means input cannot cross this size.</p> <p> <strong>Let's understand through an example.</strong> </p> <pre> #include #include using namespace std; int main() { char fruits[50]; // array declaration cout<< 'Enter your favorite fruit: '; cin.getline(fruits, 50); // implementing getline() function std::cout << '
Your favorite fruit is :'<<fruits << std::endl; return 0; } < pre> <p> <strong>Output</strong> </p> <pre> Enter your favorite fruit: Watermelon Your favorite fruit is: Watermelon </pre> <hr></fruits></pre></\'
profile> Pole znakov Getline
Pre pole znakov môžeme definovať aj funkciu getline(), ale jej syntax je odlišná od predchádzajúcej.
Syntax
istream& getline(char* , int size);
Vo vyššie uvedenej syntaxi sú dva parametre; jeden je char *, a druhý je veľkosť .
Kde,
znak*: Je to znakový ukazovateľ, ktorý ukazuje na pole.
Veľkosť: Funguje ako oddeľovač, ktorý definuje veľkosť poľa, čo znamená, že vstup nemôže prekročiť túto veľkosť.
Poďme to pochopiť na príklade.
#include #include using namespace std; int main() { char fruits[50]; // array declaration cout<< 'Enter your favorite fruit: '; cin.getline(fruits, 50); // implementing getline() function std::cout << '
Your favorite fruit is :'<<fruits << std::endl; return 0; } < pre> <p> <strong>Output</strong> </p> <pre> Enter your favorite fruit: Watermelon Your favorite fruit is: Watermelon </pre> <hr></fruits>