# Education is not limited to just classrooms. It can be gained anytime, anywhere... - Ravi Ranjan (M.Tech-NIT)

In this tutorial we are going to see how we can use relational operators in an expression.

## Relational operators in an expression

First of all we are going to list out the different relational operators.

Operator,Name of Operator
>,Greater Than
<,Less Than >=,Greater than Operator
<=,Less than Operator ==,Comparison Operator !=,Not equal to Operator [/table]

Use of relational operators in an expression is nothing but using if statement in an expression indirectly

## Reading expression containing relational operators

If we use any of the operator listed in above table in your expression then that part of expression will provide you either 0 or 1 as a result. Consider below example –

`res = 100 > 20`

above expression will assign value 1 to a variable `res` because relational operators in an expression is used. Consider below example –

### Thumb rules for solving expression

Keep in mind simple 2 thumb rules when you find relational operators in an expression –

1. Check whether the expression is true or false. If expression is true then simply replace the expression with 1
2. If expression results into false statement then replace the expression with 0

## Examples

### Example #1 : Usage of relational operator

```#include <stdio.h>
int main(int argc, char *argv[]) {

int num1 = 100;
int num2 = 100;

printf("%d",num1 >  num2);
printf("%d",num1 >= num2);
printf("%d",num1 <= num2);
printf("%d",num1 <  num2);

return 0;
}```

Output :

`0 1 1 0`

You can see, we have used the relational operators inside the expression and it returns the result with values either 0 or 1. Operation is similar to below statement –

```if(num1 > num2)
printf("1");
else
printf("0");```

### Example #2 : Indirect use of if statement

```#include<stdio.h>
void main()
{
int num1 = 100,num2=200,num3;
num3 = ( num1 >= 100 ) + (num2 < 50 );
printf("%d",num3);
}
```

Output :

`1`

Explanation :

Consider this statement –

`num3 = ( num1 >= 100 );`

above statement can be written in following way –

```if( num1 >= 100 )
num3 = 1;
else
num3 = 0;```

considering above thumb rules we can calculate the value of num3 as –

```num3 = ( num1 >= 100 ) + (num2 < 50 );
num3 = 1 + (num2 < 50 );  // ( num1 >= 100 ) is True
num3 = 1 + 0;             // ( num2 <  50  ) is False
num3 = 1;```