Difference between revisions of "C-and-C++/C2/Relational-Operators/English"

Relational operators like

Less than: eg. a < b

Greater than: eg. a > b

Less than or equal to: eg. a <= b

Greater than or equal to: eg. a >= b

Equal to: eg. a == b

And Not equal to: eg. a != b

• Ubuntu 11.10 as the operating system and

• gcc and g++ Compiler version 4.6.1 on Ubuntu.

Return values:

0 when False

1 when True

Relational operators are used to compare integer and floating point numbers.

Expressions using relational operators return 0 for false and 1 for true.

So, I'll open the editor and explain the code.

int a,b;

printf("Enter the values of a and b\n");

scanf("%d %d",&a,&b);

if(a > b)

This operator compares the two operands on either side of the operator.

It returns true if a is greater than b.

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

If the above condition is false, then it is skipped.

The control then jumps to the next statement.

else if(a < b)

This, too, compares the operands.

It returns true when a is less than b.

printf("%d is less than %d \n",a,b);

It is skipped otherwise.

/*

*/

First comment out the following.

Type /* */

I have saved my file as relational.c

gcc relational.c -o rel

Type

./rel

gcc space relational.c space -o space rel

Press Enter.

To execute the code, type

./rel

Press Enter.

8 is greater than 3.

The output is displayed: 8 is greater than 3.

You can try executing this code with different values of a and b.

/*

Retype

/*

Delete the comment from here and put it here.

if(a <= b)

This operator compares the two operands on either side of the operator.

It returns true if a is less than or equal to 2.

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

If the above condition is false, then it is skipped.

The control then jumps to the next statement.

else if(a >= b)

It compares a and b and returns true if a is greater than or equal to b.

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

Click on Save.

Switch back to the terminal.

Compile and execute as before.

8 is greater than or equal to 3

The output is displayed:

8 is greater than or equal to 3

/*

*/

Delete the multiline comments from here and here.

if(a == b)

It is denoted by double equal (==) signs.

This operator returns true when both operands are equal to one another.

printf("%d is equal to %d \n",a,b);

If not, the control then jumps on to the next statement.

else if (a != b)

This operator returns true when the operands are not equal to one another.

printf("%d is not equal to %d \n”,a,b);

return 0;

}

return 0;

Compile and execute as before.

8 is not equal to 3

The output is displayed on the screen:

8 is not equal to 3

So, we see how the relational operators work.

Try executing this code with different set of inputs.

There are a few differences in the syntax.

I have already made the code in C++.

//Relational Operators in C++

#include <iostream>

using namespace std;

int main()

{

int a, b;

cout <<"Enter the values of a and b \n";

cin >>a >>b;

if(a > b)

cout <<a <<" is greater than " <<b <<"\n";

else if(a < b)

cout <<a <<" is less than " <<b <<"\n";

if(a <= b)

cout <<a <<" is less than or equal to " <<b <<"\n";

if(a >= b)

cout <<a <<" is greater than or equal to " <<b <<"\n";

if(a == b)

cout <<a <<" is equal to " <<b <<"\n";

else if (a != b)

cout <<a <<" is not equal to "<< b <<" \n";

return 0;

}

#include<iostream>

using namespace std;

cout

Also we have the using statement here.

The output statement in C++ is cout.

And the input statement in C++ is cin.

So, apart from these differences, the two codes are very similar.

Please make sure the file is saved with extension .cpp

I have saved my file as relational.cpp

g++ relational.cpp -o rel

./rel

Open the terminal and type

g++ relational.cpp space -o space rel1

To execute, type

./ rel1 Press Enter

The output is displayed.

We see that the output is same as the one in C program.

Come back to our program.

Come back to out terminal.

Compile and execute as before.

Come back to our program.

This is because here we have an assignment operator.

So value of b is assigned to a.

Type an equal to sign.

Click on Save

Compile and execute as before.

The output is now correct.

In this tutorial, we learnt

Relational operators like

Less than: eg. a <b

Greater than: eg. a>b

Less than or equal to: eg. a<=b

Greater than or equal to: eg. a>=b

Equal to: eg. a==b

Not equal to: eg. a!=b

Write a program that takes the marks of three students as input.

Compare the marks to see which student has scored the highest.

Check also if two or more students have scored equal marks.

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