Logische Operatoren führen logische Operationen an einem bestimmten Ausdruck durch, indem sie zwei oder mehr Ausdrücke oder Bedingungen verbinden. Es kann in verschiedenen relationalen und bedingten Ausdrücken verwendet werden. Dieser Operator basiert auf booleschen Werten, um die Bedingung logisch zu überprüfen. Wenn die Bedingungen wahr sind, gibt er 1 zurück. Andernfalls gibt er 0 (Falsch) zurück. In der C-Programmierung werden logische Operatoren in drei Typen eingeteilt, z. B. den logischen UND-Operator (&&), den logischen ODER-Operator (||) und den logischen NICHT-Operator (!). Hier lernen wir den logischen UND-Operator und seine verschiedenen Beispiele in der Programmiersprache C kennen.
Logischer UND-Operator
Der logische UND-Operator wird als doppeltes kaufmännisches Und-Symbol „&&“ dargestellt. Es prüft die Bedingung von zwei oder mehr Operanden durch Kombination in einem Ausdruck. Wenn alle Bedingungen wahr sind, gibt der logische UND-Operator den booleschen Wert wahr oder 1 zurück. Andernfalls gibt er falsch oder 0 zurück.
Hinweis: Wenn der Wert beider Werte ungleich Null ist, bleibt die Bedingung wahr. Andernfalls gibt der logische UND-Operator (&&) 0 (falsch) zurück.
Syntax
(condition1 && condition2)
In der obigen Syntax gibt es zwei Bedingungen, Bedingung1 und Bedingung2, und dazwischen das doppelte (&&) kaufmännisches Und-Symbol. Wenn beide Bedingungen wahr sind, gibt der logische UND-Operator den booleschen Wert 1 oder wahr zurück. Andernfalls wird false zurückgegeben.
Wahrheitstabelle des logischen UND-Operators (&&).
| A | B | A && B |
|---|---|---|
| 1 | 1 | 1 |
| 1 | 0 | 0 |
| 0 | 1 | 0 |
| 0 | 0 | 0 |
Beispiel 1: Programm zur Demonstration des logischen UND-Operators in C
#include #include int main () { // declare variable int n = 20; // use Logical AND (&&) operator to check the condition printf (' %d
', (n == 20 && n >= 8)); // condition is true, therefore it returns 1 printf (' %d
', (n >= 1 && n >= 20)); printf (' %d
', (n == 10 && n >= 0)); printf (' %d
', (n >= 20 && n <= 40)); return 0; } < pre> <p> <strong>Output</strong> </p> <pre> 1 1 0 1 </pre> <p> <strong>Example 2: Program to find the largest number using the Logical AND operator</strong> </p> <pre> #include #include int main () { // declare integer type variable int x, y, z; printf (' Enter the first number: '); scanf ('%d', &x); printf (' Enter the second number: '); scanf ('%d', &y); printf (' Enter the third number: '); scanf ('%d', &z); // use logical AND operator to validate the condition if ( x >= y && x >= z ) { printf (' %d is the largest number of all. ', x); } else if ( y >= x && y >= z) { printf (' %d is the largest number of all. ', y); } else { printf ( ' %d is the largest number of all. ', z); } return 0; } </pre> <p> <strong>Output</strong> </p> <pre> Enter the first number: 20 Enter the second number: 10 Enter the third number: 50 50 is the largest number of all </pre> <p> <strong>Example 3: Program to use the Logical AND (&&) operator to check whether the user is teenager or not.</strong> </p> <pre> #include #include int main () { // declare variable int age; printf (' Enter the age: '); scanf (' %d', &age); // get age // use logical AND operator to check more than one condition if ( age >= 13 && age <= 19) { printf (' %d is a teenager age. ', age); } else not return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter the age: 17 17 is a teenager age. 2nd execution: Enter the age: 10 10 is not a teenager age. </pre> <p> <strong>Example 4: Program to validate whether the entered number is in the defined range or not.</strong> </p> <pre> #include int main () { int num; printf (' Enter a number between 1 to 50: '); scanf (' %d', &num); //get the number // use logical AND operator to check condition if ( (num > 0 ) && (num 50 ) && ( num <= 50 100)) { printf (' the entered number is in range and 100. '); } else please enter defined range. return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a number between 1 to 50: 19 The entered number is in the range 0 and 50. 2nd Run Enter a number between 1 to 50: 51 The entered number is in the range 50 and 100. 3rd execution: Enter a number between 1 to 50: 0 Please enter the number is in the defined range. </pre> <p> <strong>Example 5: Program to validate the username and password entered by the user is correct or not using the predefined username and password.</strong> </p> <pre> #include #include // use #define macro to define the values for UserName and Password #define UserName 'system' #define Password 'admin@123' int main () { // declare character type array char un[50], pass[50]; // take UserName and Password from user printf ( ' Enter the username: ' ); scanf (' %s', un); printf ( ' Enter the password: ' ); scanf (' %s', pass); // use if statement and Logical AND operator to validate the condition if (strcmp (UserName, un) == 0 && strcmp (Password, pass) == 0) { printf ('
The user's credentials are correct. '); } else { printf ( '
The user's credentials are incorrect. '); } return 0; } </pre> <p> <strong>Output</strong> </p> <pre> Enter the username: system Enter the password: admin@123 The user's credentials are correct. 2nd execution Enter the username: system Enter the password: admin@1234 The user's credentials are incorrect. </pre> <hr></=></pre></=></pre></=> Beispiel 2: Programm zum Ermitteln der größten Zahl mithilfe des logischen UND-Operators
#include #include int main () { // declare integer type variable int x, y, z; printf (' Enter the first number: '); scanf ('%d', &x); printf (' Enter the second number: '); scanf ('%d', &y); printf (' Enter the third number: '); scanf ('%d', &z); // use logical AND operator to validate the condition if ( x >= y && x >= z ) { printf (' %d is the largest number of all. ', x); } else if ( y >= x && y >= z) { printf (' %d is the largest number of all. ', y); } else { printf ( ' %d is the largest number of all. ', z); } return 0; } Ausgabe
Enter the first number: 20 Enter the second number: 10 Enter the third number: 50 50 is the largest number of all
Beispiel 3: Programm zur Verwendung des logischen UND-Operators (&&), um zu prüfen, ob der Benutzer ein Teenager ist oder nicht.
#include #include int main () { // declare variable int age; printf (' Enter the age: '); scanf (' %d', &age); // get age // use logical AND operator to check more than one condition if ( age >= 13 && age <= 19) { printf (\' %d is a teenager age. \', age); } else not return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter the age: 17 17 is a teenager age. 2nd execution: Enter the age: 10 10 is not a teenager age. </pre> <p> <strong>Example 4: Program to validate whether the entered number is in the defined range or not.</strong> </p> <pre> #include int main () { int num; printf (' Enter a number between 1 to 50: '); scanf (' %d', &num); //get the number // use logical AND operator to check condition if ( (num > 0 ) && (num 50 ) && ( num <= 50 100)) { printf (\' the entered number is in range and 100. \'); } else please enter defined range. return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a number between 1 to 50: 19 The entered number is in the range 0 and 50. 2nd Run Enter a number between 1 to 50: 51 The entered number is in the range 50 and 100. 3rd execution: Enter a number between 1 to 50: 0 Please enter the number is in the defined range. </pre> <p> <strong>Example 5: Program to validate the username and password entered by the user is correct or not using the predefined username and password.</strong> </p> <pre> #include #include // use #define macro to define the values for UserName and Password #define UserName 'system' #define Password 'admin@123' int main () { // declare character type array char un[50], pass[50]; // take UserName and Password from user printf ( ' Enter the username: ' ); scanf (' %s', un); printf ( ' Enter the password: ' ); scanf (' %s', pass); // use if statement and Logical AND operator to validate the condition if (strcmp (UserName, un) == 0 && strcmp (Password, pass) == 0) { printf ('
The user's credentials are correct. '); } else { printf ( '
The user's credentials are incorrect. '); } return 0; } </pre> <p> <strong>Output</strong> </p> <pre> Enter the username: system Enter the password: admin@123 The user's credentials are correct. 2nd execution Enter the username: system Enter the password: admin@1234 The user's credentials are incorrect. </pre> <hr></=></pre></=> Beispiel 4: Programm zur Validierung, ob die eingegebene Zahl im definierten Bereich liegt oder nicht.
#include int main () { int num; printf (' Enter a number between 1 to 50: '); scanf (' %d', &num); //get the number // use logical AND operator to check condition if ( (num > 0 ) && (num 50 ) && ( num <= 50 100)) { printf (\' the entered number is in range and 100. \'); } else please enter defined range. return 0; < pre> <p> <strong>Output</strong> </p> <pre> Enter a number between 1 to 50: 19 The entered number is in the range 0 and 50. 2nd Run Enter a number between 1 to 50: 51 The entered number is in the range 50 and 100. 3rd execution: Enter a number between 1 to 50: 0 Please enter the number is in the defined range. </pre> <p> <strong>Example 5: Program to validate the username and password entered by the user is correct or not using the predefined username and password.</strong> </p> <pre> #include #include // use #define macro to define the values for UserName and Password #define UserName 'system' #define Password 'admin@123' int main () { // declare character type array char un[50], pass[50]; // take UserName and Password from user printf ( ' Enter the username: ' ); scanf (' %s', un); printf ( ' Enter the password: ' ); scanf (' %s', pass); // use if statement and Logical AND operator to validate the condition if (strcmp (UserName, un) == 0 && strcmp (Password, pass) == 0) { printf ('
The user's credentials are correct. '); } else { printf ( '
The user's credentials are incorrect. '); } return 0; } </pre> <p> <strong>Output</strong> </p> <pre> Enter the username: system Enter the password: admin@123 The user's credentials are correct. 2nd execution Enter the username: system Enter the password: admin@1234 The user's credentials are incorrect. </pre> <hr></=> Beispiel 5: Programm zur Überprüfung des vom Benutzer eingegebenen Benutzernamens und Passworts auf Richtigkeit oder Verwendung des vordefinierten Benutzernamens und Passworts.
#include #include // use #define macro to define the values for UserName and Password #define UserName 'system' #define Password 'admin@123' int main () { // declare character type array char un[50], pass[50]; // take UserName and Password from user printf ( ' Enter the username: ' ); scanf (' %s', un); printf ( ' Enter the password: ' ); scanf (' %s', pass); // use if statement and Logical AND operator to validate the condition if (strcmp (UserName, un) == 0 && strcmp (Password, pass) == 0) { printf ('
The user's credentials are correct. '); } else { printf ( '
The user's credentials are incorrect. '); } return 0; } Ausgabe
Enter the username: system Enter the password: admin@123 The user's credentials are correct. 2nd execution Enter the username: system Enter the password: admin@1234 The user's credentials are incorrect.