What is the relational operator in C?

• Logical operators are used to perform logical operations on the given expressions.
• There are 3 logical operators in C language. They are,

1. logical AND (&&)
2. logical OR (||)
3. logical NOT (!)

• Bitwise operators are used to perform bit operations. Decimal values are converted into binary values which are the sequence of bits and bit wise operators work on these bits.
• Bit wise operators in C language are & (bitwise AND), | (bitwise OR), ~ (bitwise OR), ^ (XOR), << (left shift) and >> (right shift).

There are 3 types of decision making control statements in C language. They are,

1. if statements
2. if else statements
3. nested if statements

• Loop control statements in C are used to perform looping operations until the given condition is true. Control comes out of the loop statements once condition becomes false.
• There are 3 types of loop control statements in C language. They are,

1. for
2. while
3. do-while

• While loop is executed only when given condition is true.
• Whereas, do-while loop is executed for first time irrespective of the condition. After executing while loop for first time, then condition is checked.

• Pre increment operator is used to increment variable value by 1 before assigning the value to the variable.
• Post increment operator is used to increment variable value by 1 after assigning the value to the variable.

• Pre decrement operator is used to decrement variable value by 1 before assigning the value to the variable.
• Post decrement operator is used to decrement variable value by 1 after assigning the value to the variable.

• * Operator is used as pointer to a variable. Example: * a where * is pointer to the variable a.
• & operator is used to get the address of the variable. Example: &a will give address of a.

Explanation

Practical Example

The address-of operator (&) in C is used to get the memory address of a variable. Here is an example:

#include <stdio.h>

int main() {
    int x = 5;
    printf("The memory address of x is: %p\n", &x);
    return 0;
}

In this example, the variable x is initialized with the value of 5, and the address of x is printed using the address-of operator and the %p format specifier. The output would be something like "The memory address of x is: 0x7ffc6f9a6b24"

The dereference operator * in C is used to get the value stored at a memory address. Here is an example:

#include <stdio.h>

int main() {
    int x = 5;
    int *ptr = &x;
    printf("The value of x is: %d\n", *ptr);
    return 0;
}

In this example, the variable x is initialized with the value of 5, the memory address of x is stored in ptr and finally, the value stored at the memory address of x is printed using the dereference operator * and the %d format specifier. The output would be something like "The value of x is: 5"

• Switch case statements are used to execute only specific case statements based on the switch expression.
• If we do not use break statement at the end of each case, program will execute all consecutive case statements until it finds next break statement or till the end of switch case block.

Example

If the break statement is not used in a switch case in C, the code will continue to execute the next case statement(s) after a match is found.

For example:

switch (x) {
    case 1: 
        printf("Case 1");
    case 2: 
        printf("Case 2");
    case 3: 
        printf("Case 3");
}

If the value of x is 1, the output will be "Case 1Case 2Case 3". This is because after the first match, the code continues to execute the next case statements, instead of breaking out of the switch statement with the use of the break statement.

To avoid this problem, the break statement should be used at the end of each case block.

switch (x) {
    case 1: 
        printf("Case 1");
        break;
    case 2: 
        printf("Case 2");
        break;
    case 3: 
        printf("Case 3");
        break;
}

This way, when the program reaches the matching case, it will break out of the switch statement and will not execute any other cases.

Switch case statements are used to execute only specific case statements based on the switch expression. If switch expression does not match with any case, default statements are executed by the program.

Example

int x = 3;

switch (x) {
    case 1:
        printf("x is 1");
        break;
    case 2:
        printf("x is 2");
        break;
    default:
        printf("x is not 1 or 2");
        break;
}

In this example, if x=3 which is not handled by any of the case statement, the default statement will be executed.