## Introduction to Expression in C

An expression in C is defined as 2 or more operands are connected by one operator and which can also be said to a formula to perform any operation. An operand is a function reference, an array element, a variable, or any constant. An operator is symbols like “+”, “-“, “/”, “*” etc.

**Let’s observe this example:**

A*B

In the above expression multiplication symbol (*) is said to be an operator and A and B are said to be 2 operands.

### Types of Expression in C

In C there are 4 types of expressions.

- Arithmetic expressions
- Relational expressions
- Logical expressions
- Conditional expressions

Every expression of these 4 types takes certain types of operands and used a specific type of operators. The result of this expression operation produces a specific value.

**Example:**

addition=(12/5)+(A-B);

From this line after equal operator(=) is an expression((12/5)+(A-B)) and total line is said to be a statement(addition=(12/5)+(A-B);).

### How does Expressions works in C?

Expressions in C are built from combinations of operators, let’s see them as described below.

#### 1. Arithmetic Expressions

Addition (+), Subtraction(-), Multiplication(*), Division(/), Modulus(%), Increment(++) and Decrement(–) operators are said to “Arithmetic expressions”. This operator works in between operands. like A+B, A-B, A–, A++ etc.

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**Syntax:**

`A+B;`

A-B;

A*B;

A/B;

**Example:**

**Code: **

`//used to include basic C libraries`

#include <stdio.h>

//main method for run c application

int main()

{

//declaring variables

int a,b,result;

//Asking the user to enter 2 numbers

printf("Enter 2 numbers for Arithmetic operation \n");

//Storing 2 numbers in varaibles a and b

scanf("%d\n%d",&a,&b);

//Arithmetic operations and its result displaying

result = a+b;

printf("================ARITHMETIC EXPRESSIONS==============\n");

printf("Addition of %d and %d is = %d \n",a,b,result);

result = a-b;

printf("Subtraction of %d and %d is = %d \n",a,b,result);

result = a*b;

printf("Multiplication of %d and %d is = %d \n",a,b,result);

result = a/b;

printf("Division of %d and %d is = %d \n",a,b,result);

result = a%b;

printf("Modulus(Remainder) when %d divided by %d = %d \n",a,b,result);

int c=a;

result = a++;

printf("Post Increment of %d is = %d \n",c,result);

result = ++a;

printf("Pre Increment of %d is = %d \n",c,result);

result=a--;

printf("Post decrement of %d is = %d \n",c,result);

result=--a;

printf("Pre decrement of %d is = %d \n",c,result);

printf("==========================================");

return 0;

}

**Output:**

** **

### 2. Relational Expressions

== (equal to), != (not equal to), != (not equal to), > (greater than), < (less than), >= (greater than or equal to), <= (less than or equal to) operators are said to “Relational expressions”.This operators works in between operands. Used for comparing purpose. Like A==B, A!=B, A>B, A<B etc.

**Syntax:**

`A==B;`

A!=B;

A<B;

A>B;

**Example:**

**Code: **

`//used to include basic C libraries`

#include <stdio.h>

//include boolean library in c

#include <stdbool.h>

//main method for run c application

int main()

{

//declaring variables

int a,b;

bool result;

//Realational Expressions and its result displaying

printf("================RELATIONAL EXPRESSIONS==============\n");

//equal expression

a=10, b=10;

result=(a==b);

if(result)

{

printf("%d and %d are equal\n",a,b);

}

//not equal expression

a=10, b=5;

result=(a!=b);

if(result)

{

printf("%d and %d are not equal\n",a,b);

}

//greater expression

a=10, b=20;

result=(a<b);

if(result)

{

printf("%d is greater than %d\n",a,b);

}

//lesser expression

b=10, a=20;

result=(a>b);

if(result)

{

printf("%d is less than %d\n",b,a);

}

printf("==========================================");

return 0;

}

**Output:**

** **

#### 3. Logical Expressions

&&(Logical and), ||(Logical or) and !(Logical not) operators are said to “Logical expressions”. Used to perform a logical operation. This operator works in between operands. Like A&&B, A||B,A!B etc.

**Syntax:**

`A&&B;`

A||B;

A!B;

**Example:**

**Code: **

`//used to include basic C libraries`

#include <stdio.h>

//include boolean library in c

#include <stdbool.h>

//main method for run c application

int main()

{

//declaring variables

int a,b;

bool result;

//Logical Expressions and its result displaying

printf("================LOGICAL EXPRESSIONS==============\n");

//logical and(&&) expression

a=10, b=20;

result=(a>5&&b>10);

if(result)

{

printf("I AM LOGICAL AND RESULT\n");

}

//logical or(||) expression

a=10, b=5;

result=(a>10||b>4);

if(result)

{

printf("I AM LOGICAL OR RESULT\n");

}

//logical not(!) expression

a=10, b=5;

result=(!(a==20));

if(result)

{

printf("I AM LOGICAL NOT RESULT\n");

}

printf("==========================================");

return 0;

}

**Output:**

#### 4. Conditional Expressions

?(Question mark) and :(colon) are said to “Conditional expressions”. Used to perform a conditional check. It has 3 expressions first expression is condition. If it is true then execute expression2 and if it is false then execute expression3. Like (A>B)?”A is Big”:”B is Big”.

**Syntax:**

`(X+2=10)?'true':'false';`

**Example:**

**Code: **

`//used to include basic C libraries`

#include <stdio.h>

//include boolean library in c

#include <stdbool.h>

//main method for run c application

int main()

{

//declaring variables

int a,b;

char result;

//Asking the user to enter a number

printf("Enter a number for conditional operation=>");

//Storing a number in varaibles a

scanf("%d",&a);

//Realational Expressions and its result displaying

printf("================CONDITIONAL EXPRESSIONS==============\n");

//conditional expression

result=(a>=18)?'Y':'N';

if(result=='Y')

{

printf("YOU ARE ELIGIBLE FOR VOTER ID\n");

}

else

{

printf("YOU ARE NOT ELIGIBLE FOR VOTER ID\n");

}

printf("==========================================");

return 0;

}

**Output:**

### Conclusion

Expression in C is said to be a formula which is formed 2 or more operands and one operator. Arithmetic expressions, Logical expressions, Conditional expressions and Relational expressions are some of the expressions in C.

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