What is Boolean in C?

Boolean is a data type in C that represents logical values. It can have two possible values: true or false. In C, true is represented by the integer value 1 and false is represented by the integer value 0.

Boolean is used in C to perform logical operations and to make decisions based on the result of these operations. For example, if we want to check if a certain condition is true or false, we can use a Boolean variable to store the result of this check and then use it in a conditional statement to execute different blocks of code based on the value of the Boolean variable.

Syntax:

bool variable_name;

This declares a Boolean variable with the name variable_name.

Example:

bool is_sunny = true;

In above example, we declare a Boolean variable called is_sunny and initialize it with the value true.

Different ways to write Boolean in C:

1. Using the bool keyword:

bool is_sunny = true;

2. Using the int data type with the values 0 and 1:

int is_sunny = 1;

3. Using the char data type with the values ‘0’ and ‘1’:

char is_sunny = '1';

All these methods are equivalent and can be used interchangeably. The choice of method depends on personal preference and coding style.

Examples of Boolean:

#include <stdio.h>
#include <stdbool.h>

int main() {
    bool is_sunny = true;
    int temperature = 25;

    if (is_sunny && temperature > 20) {
        printf("It's a nice day.\n");
    } else {
        printf("It's not a nice day.\n");
    }

    return 0;
}

Output:

It's a nice day.

Explanation:

In above example, we declare a Boolean variable called is_sunny and initialize it with the value true. We also declare an integer variable called temperature and initialize it with the value 25. We then use the if statement to check if is_sunny is true and if the temperature is greater than 20. Since both conditions are true, the program prints “It’s a nice day.” to the console.

Boolean using Array and Typedef:

Boolean can also be used as an array or as a typedef. When used as an array, Boolean can store multiple true/false values. When used as a typedef, Boolean can be given a custom name, which can make the code more readable.

1. Example of Boolean using Array:

#include <stdio.h>
#include <stdbool.h>

int main() {
    bool weekdays[7] = {true, true, true, true, true, false, false};
    
    for (int i = 0; i < 7; i++) {
        if (weekdays[i]) {
            printf("Day %d is a weekday.\n", i + 1);
        } else {
            printf("Day %d is a weekend.\n", i + 1);
        }
    }
    
    return 0;
}

Output:

Day 1 is a weekday.
Day 2 is a weekday.
Day 3 is a weekday.
Day 4 is a weekday.
Day 5 is a weekday.
Day 6 is a weekend.
Day 7 is a weekend.

Explanation:

In above example, we declare an array called weekdays that contains Boolean values. Each element in the array represents a day of the week, and is true if it’s a weekday and false if it’s a weekend. We then use a for loop to iterate over each element in the array, and use an if statement to check whether the current day is a weekday or a weekend. Finally, we print a message to the console indicating whether the current day is a weekday or a weekend.

2. Example of Boolean using Typedef:

#include <stdio.h>
#include <stdbool.h>

typedef bool Status;

int main() {
    Status is_sunny = true;
    
    if (is_sunny) {
        printf("It's sunny today.\n");
    } else {
        printf("It's not sunny today.\n");
    }
    
    return 0;
}

Output:

It's sunny today.

In above example, we use the typedef keyword to create a new data type called Status that is equivalent to bool. We then declare a variable called is_sunny of type Status, which can only have the values true or false. We use an if statement to check whether is_sunny is true or false, and print a message to the console accordingly.

Boolean using Logical Operators:

Boolean can also be used with logical operators such as && (AND), || (OR), and ! (NOT). These operators allow us to combine multiple Boolean expressions and perform logical operations on them.

1. Boolean using && (AND) Logical Operator:

#include <stdio.h>
#include <stdbool.h>

int main() {
    bool isSunny = true;
    bool isWarm = true;

    if (isSunny && isWarm) {
        printf("It's a great day for a picnic!\n");
    } else {
        printf("Sorry, the weather is not suitable for a picnic.\n");
    }
    
    return 0;
}

Output:

It's a great day for a picnic!

Explanation:

In above example, the && operator requires both isSunny and isWarm to be true for the overall expression to be true. Since both variables are true, the message “It’s a great day for a picnic!” is printed to the console.

2. Boolean using || (OR) Logical Operator:

#include <stdio.h>
#include <stdbool.h>

int main() {
    bool isRaining = true;
    bool isSnowing = false;

    if (isRaining || isSnowing) {
        printf("Be sure to bring your umbrella.\n");
    } else {
        printf("No need for an umbrella today.\n");
    }
    
    return 0;
}

Output:

Be sure to bring your umbrella.

Explanation:

In this example, the || operator requires either isRaining or isSnowing to be true for the overall expression to be true. Since isRaining is true, the message “Be sure to bring your umbrella.” is printed to the console.

3. Boolean using ! (NOT) Logical Operator:

#include <stdio.h>
#include <stdbool.h>

int main() {
    bool isRaining = true;

    if (!isRaining) {
        printf("No need for an umbrella today.\n");
    } else {
        printf("Be sure to bring your umbrella.\n");
    }
    
    return 0;
}

Output:

Be sure to bring your umbrella.

Explanation:

In this example, the ! operator negates the value of isRaining. Since isRaining is true, the negated value is false. Therefore, the message “Be sure to bring your umbrella.” is printed to the console.

Rules to follow while using Boolean in C:

1. Boolean variables should be declared using the bool keyword or a compatible data type such as int or char.
2. Boolean variables should be initialized with either the value true or false.
3. When comparing Boolean variables, use logical operators such as && and || instead of arithmetic operators such as + and -.
4. Boolean variables should be used in conditional statements such as if and while to make decisions based on the result of a logical operation.

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