What is the difference between = (Assignment) and == (Equal to) operators

= operator

The “=” is an assignment operator used to assign the value on the right to the variable on the left. 

For example:

a = 10;
b = 20;
ch = 'y';

Example:

C

// C program to demonstrate
// working of Assignment operators

#include <stdio.h>

int main()
{

    // Assigning value 10 to a
    // using "=" operator
    int a = 10;
    printf("Value of a is %d\n", a);

    return 0;
}

Output:

Value of a is 10

== operator

The ‘==’ operator checks whether the two given operands are equal or not. If so, it returns true. Otherwise it returns false. 

For example:

5==5

This will return true.

Example:

C

// C program to demonstrate
// working of relational operators
#include <stdio.h>

int main()
{
    int a = 10, b = 4;

    // equal to
    if (a == b)
        printf("a is equal to b\n");
    else
        printf("a and b are not equal\n");

    return 0;
}

Output:

a and b are not equal

The differences can be shown in tabular form as follows:

=	==
It is an assignment operator.	It is a relational or comparison operator.
It is used for assigning the value to a variable.	It is used for comparing two values. It returns 1 if both the values are equal otherwise returns 0.
Constant term cannot be placed on left hand side. Example: 1=x; is invalid.	Constant term can be placed in the left hand side. Example: 1==1 is valid and returns 1.