Za izvajanje kakršnih koli vhodnih in izhodnih operacij v C++ moramo uporabiti datoteke glave iostream. Brez datoteke glave ne moremo sprejeti vnosa od uporabnika ali natisniti izhoda.
Sintaksa datoteke glave:
#include #include 'iostream.h'
V datoteki glave iostream sta dve vrsti tokov
1. Vhodni tok : Če želimo sprejeti kakršen koli vnos od uporabnika, moramo uporabiti cin, ki pripada vhodnemu toku
Sintaksa za uporabo vhodnega toka:
std::cin>>variable_name
Ko se izvede cin, se kazalec ustavi na določenem stavku, dokler ni vnesena vrednost. Vnesena vrednost bo shranjena v spremenljivki.
2. Izhodni tok : Za tiskanje izhoda uporabljamo vgrajene funkcije v izhodnem toku cout
Sintaksa za cout
std::cout<<variable_name < pre> <p>When cout is executed, the value in the variable will be printed.</p> <h3>Different operations in iostream</h3> <p> <strong>1. Cin</strong> </p> <p>Using cin, we can take input from the user and store the value in the variable. We need to use the cin keyword followed by >> and the variable name.</p> <p> <strong>Syntax:</strong> </p> <pre> std::cin>>variable_name </pre> <p>To use cin, we need to use <strong>#include </strong> as cin belongs to this header file, and without this, an error will occur.</p> <p> <strong>Example code for cin:</strong> </p> <pre> //using header file iostream #include using namespace std; int main() { string name; //cin declaration cin >> name; return 0; } </pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c.webp" alt="What is include iostream in C++"> <p> <strong>Explanation:</strong> </p> <p>In the above code, we used cin to take the input, so to use cin, we included header file. When the input is taken, the string input is stored in the name variable.</p> <p> <strong>2. Cout</strong> </p> <p>To print the output, we need to use the cout keyword, which belongs to the iostream header file. To use cout, we need to use the cout keyword followed by << and variable or the statement to print the output.</p> <p>The syntax for using cout:</p> <pre> std::cout<<variable_name < pre> <p> <strong>Example of using cout:</strong> </p> <pre> //to use the cout statement, we need to use the iostream header file #include using namespace std; int main() { //cout statement is used here to print the statement cout << 'Hi from cout statement'; return 0;} </pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-2.webp" alt="What is include iostream in C++"> <p> <strong>Explanation</strong> :</p> <p>In the above code, we used a cout statement to print the statement. To use the cout statement, we need to include iostream.h header file. Once the cout is executed, statement or variable value will be printing the output. To print any statement, we need to use double quotes (' '), and to print a variable value; we need to use just the variable name without double quotes(' ')</p> <p> <strong>3. Cerr</strong> </p> <p>Cerr is used to print errors in C++, which is present in the iostream header file. If we need to print any error message in the code if any condition fails, then cerr is very helpful.</p> <p>The syntax for cerr is:</p> <pre> cerr<<variable_name < pre> <p>Example:</p> <pre> #include using namespace std; int main() { int a; cin>>a; if(a%2==0){ cout<<'the number entered in even number'<<endl; } else{ std::cerr << 'enter proper number' '
'; return 0; < pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-3.webp" alt="What is include iostream in C++"> <p> <strong>Explanation:</strong> </p> <p>In the above example, we used cin to take the input and check if the given number is even or not. If the given number is not even, we need to print an error that the given number is not an even number. We use the cerr keyword in the iostream header file to print this error.</p> <p> <strong>4. Clog:</strong> </p> <p>The clog is also used to print error messages, but unlike cerr, clog is buffered, which means the error message is stored in a buffer and then will be printed, but cerr is unbuffered and will not store the error message in the buffer. The clog also belongs to the iostream header file. As the clog is buffered, it will not show the error message immediately. The clog is preferred more than cerr when efficiency is more important.</p> <p>The syntax for clog:</p> <pre> clog<<variable_name; < pre> <p> <strong>Example:</strong> </p> <pre> #include using namespace std; int main() { clog << 'This message is stored in the buffer'; return 0; } </pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-4.webp" alt="What is include iostream in C++"> <p> <strong>Explanation:</strong> </p> <p>In the above code, we are printing an error. To print this error, we use cerr, which belongs to the iostream header file. Before printing the error, we store the error in a buffer.</p> <p> <strong>Example</strong> : For all the input and output streams</p> <pre> #include using namespace std; int main() { int a; string b; cin>>a; if(a%2==0){ cout<<'the number entered is even enter a name'<>b; cout< <b; } else{ std::cerr << 'enter even number' '
'; < pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-5.webp" alt="What is include iostream in C++"> <p> <strong>Explanation</strong> : In the above code, we used all the input and output streams in the iostream.h header file.</p> <hr></b;></'the></pre></variable_name;></pre></'the></pre></variable_name></pre></variable_name></pre></variable_name> Če želimo uporabiti cin, moramo uporabiti #vključi ker cin pripada tej datoteki glave, brez tega pa bo prišlo do napake.
Primer kode za cin:
//using header file iostream #include using namespace std; int main() { string name; //cin declaration cin >> name; return 0; } Izhod:
Pojasnilo:
V zgornji kodi smo za prevzem vnosa uporabili cin, zato smo za uporabo cin vključili datoteko glave. Ko je vnos sprejet, se vnos niza shrani v spremenljivko imena.
2. Cout
Za tiskanje izhoda moramo uporabiti ključno besedo cout, ki pripada datoteki glave iostream. Za uporabo cout moramo uporabiti ključno besedo cout, ki ji sledi << in spremenljivka ali stavek za tiskanje izhoda.
velikost pisave iz lateksa
Sintaksa za uporabo cout:
std::cout<<variable_name < pre> <p> <strong>Example of using cout:</strong> </p> <pre> //to use the cout statement, we need to use the iostream header file #include using namespace std; int main() { //cout statement is used here to print the statement cout << 'Hi from cout statement'; return 0;} </pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-2.webp" alt="What is include iostream in C++"> <p> <strong>Explanation</strong> :</p> <p>In the above code, we used a cout statement to print the statement. To use the cout statement, we need to include iostream.h header file. Once the cout is executed, statement or variable value will be printing the output. To print any statement, we need to use double quotes (' '), and to print a variable value; we need to use just the variable name without double quotes(' ')</p> <p> <strong>3. Cerr</strong> </p> <p>Cerr is used to print errors in C++, which is present in the iostream header file. If we need to print any error message in the code if any condition fails, then cerr is very helpful.</p> <p>The syntax for cerr is:</p> <pre> cerr<<variable_name < pre> <p>Example:</p> <pre> #include using namespace std; int main() { int a; cin>>a; if(a%2==0){ cout<<\'the number entered in even number\'<<endl; } else{ std::cerr << \'enter proper number\' \'
\'; return 0; < pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-3.webp" alt="What is include iostream in C++"> <p> <strong>Explanation:</strong> </p> <p>In the above example, we used cin to take the input and check if the given number is even or not. If the given number is not even, we need to print an error that the given number is not an even number. We use the cerr keyword in the iostream header file to print this error.</p> <p> <strong>4. Clog:</strong> </p> <p>The clog is also used to print error messages, but unlike cerr, clog is buffered, which means the error message is stored in a buffer and then will be printed, but cerr is unbuffered and will not store the error message in the buffer. The clog also belongs to the iostream header file. As the clog is buffered, it will not show the error message immediately. The clog is preferred more than cerr when efficiency is more important.</p> <p>The syntax for clog:</p> <pre> clog<<variable_name; < pre> <p> <strong>Example:</strong> </p> <pre> #include using namespace std; int main() { clog << 'This message is stored in the buffer'; return 0; } </pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-4.webp" alt="What is include iostream in C++"> <p> <strong>Explanation:</strong> </p> <p>In the above code, we are printing an error. To print this error, we use cerr, which belongs to the iostream header file. Before printing the error, we store the error in a buffer.</p> <p> <strong>Example</strong> : For all the input and output streams</p> <pre> #include using namespace std; int main() { int a; string b; cin>>a; if(a%2==0){ cout<<\'the number entered is even enter a name\'<>b; cout< <b; } else{ std::cerr << \'enter even number\' \'
\'; < pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-5.webp" alt="What is include iostream in C++"> <p> <strong>Explanation</strong> : In the above code, we used all the input and output streams in the iostream.h header file.</p> <hr></b;></\'the></pre></variable_name;></pre></\'the></pre></variable_name></pre></variable_name> Izhod:
Razlaga :
V zgornji kodi smo za tiskanje izjave uporabili stavek cout. Za uporabo stavka cout moramo vključiti datoteko glave iostream.h. Ko se cout izvede, bo stavek ali vrednost spremenljivke natisnil izhod. Če želite natisniti kateri koli stavek, moramo uporabiti dvojne narekovaje (' ') in natisniti vrednost spremenljivke; uporabiti moramo samo ime spremenljivke brez dvojnih narekovajev (' ')
3. Cerr
Cerr se uporablja za tiskanje napak v C++, ki je prisoten v datoteki glave iostream. Če moramo natisniti katero koli sporočilo o napaki v kodi, če kateri koli pogoj ne uspe, je cerr zelo koristen.
Sintaksa za cerr je:
cerr<<variable_name < pre> <p>Example:</p> <pre> #include using namespace std; int main() { int a; cin>>a; if(a%2==0){ cout<<\'the number entered in even number\'<<endl; } else{ std::cerr << \'enter proper number\' \'
\'; return 0; < pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-3.webp" alt="What is include iostream in C++"> <p> <strong>Explanation:</strong> </p> <p>In the above example, we used cin to take the input and check if the given number is even or not. If the given number is not even, we need to print an error that the given number is not an even number. We use the cerr keyword in the iostream header file to print this error.</p> <p> <strong>4. Clog:</strong> </p> <p>The clog is also used to print error messages, but unlike cerr, clog is buffered, which means the error message is stored in a buffer and then will be printed, but cerr is unbuffered and will not store the error message in the buffer. The clog also belongs to the iostream header file. As the clog is buffered, it will not show the error message immediately. The clog is preferred more than cerr when efficiency is more important.</p> <p>The syntax for clog:</p> <pre> clog<<variable_name; < pre> <p> <strong>Example:</strong> </p> <pre> #include using namespace std; int main() { clog << 'This message is stored in the buffer'; return 0; } </pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-4.webp" alt="What is include iostream in C++"> <p> <strong>Explanation:</strong> </p> <p>In the above code, we are printing an error. To print this error, we use cerr, which belongs to the iostream header file. Before printing the error, we store the error in a buffer.</p> <p> <strong>Example</strong> : For all the input and output streams</p> <pre> #include using namespace std; int main() { int a; string b; cin>>a; if(a%2==0){ cout<<\'the number entered is even enter a name\'<>b; cout< <b; } else{ std::cerr << \'enter even number\' \'
\'; < pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-5.webp" alt="What is include iostream in C++"> <p> <strong>Explanation</strong> : In the above code, we used all the input and output streams in the iostream.h header file.</p> <hr></b;></\'the></pre></variable_name;></pre></\'the></pre></variable_name> Izhod:
Pojasnilo:
V zgornji kodi natisnemo napako. Za tiskanje te napake uporabimo cerr, ki pripada datoteki glave iostream. Preden izpišemo napako, jo shranimo v medpomnilnik.
Primer : Za vse vhodne in izhodne tokove
#include using namespace std; int main() { int a; string b; cin>>a; if(a%2==0){ cout<<\\'the number entered is even enter a name\\'<>b; cout< <b; } else{ std::cerr << \\'enter even number\\' \\'
\\'; < pre> <p> <strong>Output:</strong> </p> <img src="//techcodeview.com/img/c-tutorial/23/what-is-include-iostream-c-5.webp" alt="What is include iostream in C++"> <p> <strong>Explanation</strong> : In the above code, we used all the input and output streams in the iostream.h header file.</p> <hr></b;></\\'the>