Computer Programming - Keywords

So far, we have covered two important concepts called variables and their data types. We discussed how to use int, long, and float to specify different data types. We also learnt how to name the variables to store different values.

Though this chapter is not required separately because reserved keywords are a part of basic programming syntax, we kept it separate to explain it right after data types and variables to make it easy to understand.

Like int, long, and float, there are many other keywords supported by C programming language which we will use for different purpose. Different programming languages provide different set of reserved keywords, but there is one important & common rule in all the programming languages that we cannot use a reserved keyword to name our variables, which means we cannot name our variable like int or float rather these keywords can only be used to specify a variable data type.

For example, if you will try to use any reserved keyword for the purpose of variable name, then you will get a syntax error.

#include <stdio.h>

 

main() {

 

  int float;

 

  float = 10;

 

  printf( "Value of float = %d\n", float);

}

When you compile the above program, it produces the following error −

main.c: In function 'main':

main.c:5:8: error: two or more data types in declaration specifiers

   int float;

......

Let's now give a proper name to our integer variable, then the above program should compile and execute successfully −

#include <stdio.h>

 

main() {

  int count;

 

  count = 10;

 

  printf( "Value of count = %d\n", count);

}

C Programming Reserved Keywords

Here is a table having almost all the keywords supported by C Programming language −

auto

else

long

switch

break

enum

register

typedef

case

extern

return

union

char

float

short

unsigned

const

for

signed

void

continue

goto

sizeof

volatile

default

if

static

while

do

int

struct

_Packed

double

 

 

 

Java Programming Reserved Keywords

Here is a table having almost all the keywords supported by Java Programming language −

abstract

assert

boolean

break

byte

case

catch

char

class

const

continue

default

do

double

else

enum

extends

final

finally

float

for

goto

if

implements

import

instanceof

int

interface

long

native

new

package

private

protected

public

return

short

static

strictfp

super

switch

synchronized

this

throw

throws

transient

try

void

volatile

while

 

 

Python Programming Reserved Keywords

Here is a table having almost all the keywords supported by Python Programming language −

and

exec

not

assert

finally

or

break

for

pass

class

from

print

continue

global

raise

def

if

return

del

import

try

elif

in

while

else

is

with

except

lambda

yield

We know you cannot memorize all these keywords, but we have listed them down for your reference purpose and to explain the concept of reserved keywords. So just be careful while giving a name to your variable, you should not use any reserved keyword for that programming language.