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IBPS SO IT Officer Programming Languages Notes

Jan 30 • IBPS Specialist Officer • 451 Views • No Comments on IBPS SO IT Officer Programming Languages Notes

IBPS SO IT Officer Programming Languages Notes

Programming languages

C is a general-purpose high-level language was originally developed by Dennis M. Ritchie at Bell Labs.

C has used for various functions:

  • Easy to learn
  • Structured language
  • It produces efficient programs
  • It can handle low-level activities
  • It can be compiled on a variety of computer platforms

Tokens in C

In  C program tokens are either a keyword, an identifier, a constant, a string literal, or a symbol. For example−

printf(“Hello, World! \n”);

Semicolons

Semicolon is a statement terminator. Denoted  by “;”.

print f (“hello, world);

Comments

Comments are helping text in C program and they are ignored by the compiler. Start by “/*” and end by “*/”.

Identifiers

Identifier is a name used to identify a variable, function, or any other user-defined item. An identifier starts with a letter A to Z, a to z, or an underscore ‘_’ followed by zero or more letters, underscores, and digits (0 to 9).

C is a case-sensitive programming language.

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Keywords

The following list shows the reserved words in C. These reserved words may not be used as constants or variables or any other identifier names.

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

Whitespace in C

A line containing only whitespace like comment, is known as a blank line, and a C compiler totally ignores it.

Data types in c refer for declaring variables or functions of different types. The type of a variable determines how much space it occupies in storage.

The types in C can be classified as follows −

S.N. Types & Description
1 Basic Types

They are arithmetic types and are further classified into: (a) integer types and (b) floating-point types.

2 Enumerated types

They are again arithmetic types and they are used to define variables that can only assign certain discrete integer value throughout the program.

3 The type voids

The type specifier void indicates that no value is available.

4 Derived types

They include (a) Pointer types, (b) Array types, (c) Structure types, (d) Union types and (e) Function types.

Integer Types

The following table provides the details of standard integer types with their storage sizes and value ranges −

Type Storage size Value range
char 1 byte -128 to 127 or 0 to 255
unsigned char 1 byte 0 to 255
signed char 1 byte -128 to 127
int 2 or 4 bytes -32,768 to 32,767 or -2,147,483,648 to 2,147,483,647
unsigned int 2 or 4 bytes 0 to 65,535 or 0 to 4,294,967,295
short 2 bytes -32,768 to 32,767
unsigned short 2 bytes 0 to 65,535
long 4 bytes -2,147,483,648 to 2,147,483,647
unsigned long 4 bytes 0 to 4,294,967,295

Floating-Point Types

The following table provide the details of standard floating-point types with storage sizes and value ranges and their precision −

Type Storage size Value range Precision
float 4 byte 1.2E-38 to 3.4E+38 6 decimal places
double 8 byte 2.3E-308 to 1.7E+308 15 decimal places
long double 10 byte 3.4E-4932 to 1.1E+4932 19 decimal places

The void Type

The void type specifies that no value is available. It is used in three kinds of situations −

S.N. Types & Description
1 Function returns as void There are various functions in C which do not return any value or you can say they return void. A function with no return value has the return type as void. For example, void exit (int status);
2 Function arguments as void There are various functions in C which do not accept any parameter. A function with no parameter can accept a void. For example, int rand(void);
3 Pointers to void A pointer of type void * represents the address of an object, but not its type. For example, a memory allocation function void *malloc( size_t size ); returns a pointer to void which can be casted to any data type.

Constants refer to fixed values that the program may not alter during its execution. These fixed values are also called literals.

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String Literals

String literals or constants are enclosed in double quotes “”.A string contains characters that are similar to character literals: plain characters, escape sequences, and universal characters.

“hello, dear”

“hello, \

dear”

“hello, ” “d” “ear”

Defining Constants

There are two ways in C to define constants −

  • Using #define pre-processor.
  • Using const keyword.

The #define Pre-processor

#define pre-processor directive to define a constant −

#define identifier value
The following example explains it in detail −

#include <stdio.h>

#define LENGTH 10   
#define WIDTH  5
#define NEWLINE ‘\n’
int main() {
  int area;  
  area = LENGTH * WIDTH;
  printf(“value of area : %d”, area);
  printf(“%c”, NEWLINE);
  return 0;
}

The const Keyword

Use const prefix to declare constants with a specific type as follows −

const type variable = value;
The following example explains it in detail −

#include <stdio.h>
int main() {
  const int  LENGTH = 10;
  const int  WIDTH = 5;
  const char NEWLINE = ‘\n’;
  int area;  
  area = LENGTH * WIDTH;
  printf(“value of area : %d”, area);
  printf(“%c”, NEWLINE);

  return 0;
}
Arithmetic Operators

Operator Description Example
+ Adds two operands. A + B = 30
Subtracts second operand from the first. A − B = -10
* Multiplies both operands. A * B = 200
/ Divides numerator by de-numerator. B / A = 2
% Modulus Operator and remainder of after an integer division. B % A = 0
++ Increment operator increases the integer value by one. A++ = 11
Decrement operator decreases the integer value by one. A– = 9

Relational Operators

Operator Description Example
== Checks if the values of two operands are equal or not. If yes, then the condition becomes true. (A == B) is not true.
!= Checks if the values of two operands are equal or not. If the values are not equal, then the condition becomes true. (A != B) is true.
> Checks if the value of left operand is greater than the value of right operand. If yes, then the condition becomes true. (A > B) is not true.
< Checks if the value of left operand is less than the value of right operand. If yes, then the condition becomes true. (A < B) is true.
>= Checks if the value of left operand is greater than or equal to the value of right operand. If yes, then the condition becomes true. (A >= B) is not true.
<= Checks if the value of left operand is less than or equal to the value of right operand. If yes, then the condition becomes true. (A <= B) is true.

Logical Operators

Operator Description Example
&& Called Logical AND operator. If both the operands are non-zero, then the condition becomes true. (A && B) is false.
|| Called Logical OR Operator. If any of the two operands is non-zero, then the condition becomes true. (A || B) is true.
! Called Logical NOT Operator. It is used to reverse the logical state of its operand. If a condition is true, then Logical NOT operator will make it false. !(A && B) is true.

Bitwise Operators

Operator Description Example
& Binary AND Operator copies a bit to the result if it exists in both operands. (A & B) = 12, i.e., 0000 1100
| Binary OR Operator copies a bit if it exists in either operand. (A | B) = 61, i.e., 0011 1101
^ Binary XOR Operator copies the bit if it is set in one operand but not both. (A ^ B) = 49, i.e., 0011 0001
~ Binary Ones Complement Operator is unary and has the effect of ‘flipping’ bits. (~A ) = -61, i.e,. 1100 0011 in 2’s complement form.
<< Binary Left Shift Operator. The left operands value is moved left by the number of bits specified by the right operand. A << 2 = 240 i.e., 1111 0000
>> Binary Right Shift Operator. The left operands value is moved right by the number of bits specified by the right operand. A >> 2 = 15 i.e., 0000 1111

Assignment Operators

Operator Description Example
= Simple assignment operator. Assigns values from right side operands to left side operand C = A + B will assign the value of A + B to C
+= Add AND assignment operator. It adds the right operand to the left operand and assign the result to the left operand. C += A is equivalent to C = C + A
-= Subtract AND assignment operator. It subtracts the right operand from the left operand and assigns the result to the left operand. C -= A is equivalent to C = C – A
*= Multiply AND assignment operator. It multiplies the right operand with the left operand and assigns the result to the left operand. C *= A is equivalent to C = C * A
/= Divide AND assignment operator. It divides the left operand with the right operand and assigns the result to the left operand. C /= A is equivalent to C = C / A
%= Modulus AND assignment operator. It takes modulus using two operands and assigns the result to the left operand. C %= A is equivalent to C = C % A
<<= Left shift AND assignment operator. C <<= 2 is same as C = C << 2
>>= Right shift AND assignment operator. C >>= 2 is same as C = C >> 2
&= Bitwise AND assignment operator. C &= 2 is same as C = C & 2
^= Bitwise exclusive OR and assignment operator. C ^= 2 is same as C = C ^ 2
|= Bitwise inclusive OR and assignment operator. C |= 2 is same as C = C | 2

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