23ECE105 COMPUTER PROGRAMMING

Prepared by,
Mrs. SUMITHRA R. P.
 UNIT I

Introduction, structure of C program, variables, data types, storage classes,

constants, enumeration constant, keywords, operators, expressions,
input/output statements, assignment statement conditional statements;

Number system: binary, decimal, hexadecimal, conversion between

number system types;

Introduction to tools – IDE, compilation, linking, debugging.

Operators

 C language supports a rich set of built-in operators.

 An operator is a symbol that tells the compiler to perform a
certain mathematical or logical manipulation.
 Operators are used in programs to manipulate data and variables.
 C operators can be classified into following types:
• Arithmetic operators
• Relational operators
• Logical operators
• Bitwise operators
• Assignment operators
• Conditional operators
• Special operators
Arithmetic operators
Opera Description Example
tor
+ Adds two operands. A + B = 30
− Subtracts second operand from the A − B = -10
first.
* Multiplies both operands. A * B = 200
/ Divides numerator by de-numerator. B/A=2

% Modulus Operator and remainder of B%A=0

after an integer division.
++ Increment operator increases the A++ = 11
integer value by one.
-- Decrement operator decreases the A-- = 9
integer value by one.
 Relational operators
Assume variable A holds 10 and variable B holds 20 then −
Operator Description Example
== Checks if the values of two operands are equal or (A == B) is not true.
not. If yes, then the condition becomes true.
!= Checks if the values of two operands are equal or (A != B) is true.
not. If the values are not equal, then the
condition becomes true.
> Checks if the value of left operand is greater (A > B) is not true.
than the value of right operand. If yes, then the
condition becomes true.
< Checks if the value of left operand is less than (A < B) is true.
the value of right operand. If yes, then the
condition becomes true.
>= Checks if the value of left operand is greater (A >= B) is not true.
than or equal to the value of right operand. If
yes, then the condition becomes true.
<= Checks if the value of left operand is less than or (A <= B) is true.
equal to the value of right operand. If yes, then
the condition becomes true.
Logical Operators
Opera Description Example
tor
&& Called Logical AND operator. If both the operands (A && B) is false.
are non-zero, then the condition becomes true.

|| Called Logical OR Operator. If any of the two (A || B) is true.

operands is non-zero, then the condition becomes
true.

! Called Logical NOT Operator. It is used to reverse !(A && B) is true.

the logical state of its operand. If a condition is
true, then Logical NOT operator will make it
false.
 Bitwise Operators
Operator Description Example

& Binary AND Operator copies a bit to the result if it exists (A & B) = 12, i.e., 0000
in both operands. 1100
| Binary OR Operator copies a bit if it exists in either (A | B) = 61, i.e., 0011 1101
operand.
^ Binary XOR Operator copies the bit if it is set in one (A ^ B) = 49, i.e., 0011 0001
operand but not both.
~ Binary One's Complement Operator is unary and has the (~A ) = ~(60), i.e,. -0111101
effect of 'flipping' bits.
<< Binary Left Shift Operator. The left operands value is
moved left by the number of bits specified by the right A << 2 = 240 i.e., 1111 0000
operand.

>> 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
Bitwise Operators

 Assume if A = 60; and B = 13;

 now in binary format they will be as follows:
 A = 0011 1100 B = 0000 1101
A&B = 0000 1100
A|B = 0011 1101
A^B = 0011 0001
~A = 1100 0011
Assignment Operators
Operator Description Example
= assigns values from right side operands to left a=b
side operand

+= adds right operand to the left operand and a+=b is same as a=a+b
assign the result to left

-= subtracts right operand from the left operand a-=b is same as a=a-b
and assign the result to left operand

*= mutiply left operand with the right operand a*=b is same as a=a*b
and assign the result to left operand

/= divides left operand with the right operand a/=b is same as a=a/b
and assign the result to left operand

%= calculate modulus using two operands and a%=b is same as a=a%b

assign the result to left operand
Conditional operator

 The conditional operators in C language are known by two

more names
1. Ternary Operator
2. ? : Operator
It is actually the if condition that we use in C language decision
making, but using conditional operator, we turn the if condition
statement into a short and simple operator.
The syntax of a conditional operator is :
expression 1 ? expression 2: expression 3
Special operator
Operator Description Example
sizeof Returns the size of an sizeof(x) return size
variable of the variable x

& Returns the address of an &x ; return address

variable of the variable x

* Pointer to a variable *x ; will be pointer

to a variable x
Operators Precedence in C
 Operator precedence determines the grouping of terms in an
expression and decides how an expression is evaluated.
Category Operator Associativity
Postfix () [] -> . ++ - - Left to right
Unary + - ! ~ ++ - - (type)* & sizeof Right to left

Multiplicative */% Left to right

Additive +- Left to right
Shift << >> Left to right
Relational < <= > >= Left to right
Equality == != Left to right
Bitwise AND & Left to right
Bitwise XOR ^ Left to right
Bitwise OR | Left to right
Logical AND && Left to right
Logical OR || Left to right
Conditional ?: Right to left
Assignment = += -= *= /= %=>>= <<= &= ^= |= Right to left

Comma , Left to right

Give the output

#include "stdio.h"
int main()
{
int x, y = 5, z = 5;
x = y == z;
printf("%d", x);

return 0;
}
Ex:2

#include <stdio.h>

int main()
{
int i = 1, 2, 3;

printf("%d", i);

return 0;
}
Output
10 24
11 25
12 26
EX.3

#include <stdio.h>

int main()
{
int i = (1, 2, 3);

printf("%d", i);

return 0;
}
#include <stdio.h>

int main()
{
int a = 1;
int b = 1;
int c = a || --b;
int d = a-- && --b;
printf("a = %d, b = %d, c = %d, d = %d", a, b, c, d);
return 0;
}
OUTPUT :a = 0, b = 0, c = 1, d = 0
#include <stdio.h>  expression c > b > a is evaluated
as ( (c > b) > a ). And since the (c
int main()
> b) is being the relational
{ operator it will return 1 if True
otherwise 0 is if False. So here
int a = 10, b = 20, c = 30; the value returned is 1 and then
if (c > b > a) it is compared to the a. so now,
the statement becomes, (1 > a),
printf("TRUE"); which is false, so the answer,
else return is 0, therefore, else part is
executed.
printf("FALSE");
return 0;
}
# include <stdio.h>  The main statement in
question is "x += y +=
int main()
10". Since there are two
{ += operators in the
int x = 10; statement, associativity
comes into the picture.
int y = 20; Associativity of
x += y += 10; compound assignment
operators is right to left,
printf (" %d %d", x, y); so the expression is
return 0; evaluated as x += (y +=
10).
}
Thank you