Binary Number System

Binary Number System is a number system that is used to represent various numbers using only two symbols “0” and “1”. The word binary is derived from the word “bi” which means two. Hence, this number system is called Binary Number System. Thus, the binary number system is a system that has only two symbols.

Octal Number System

Octal Number System is a number system with base 8 as it uses eight symbols (or digits) namely 0, 1, 2, 3, 4, 5, 6, and 7. For example, 228, 138, 178, etc. are octal numbers. This number system is mainly used in computer programming as it is a compact way of representing binary numbers with each octal number corresponding to three binary digits.

Exercise:

Convert the following to decimal:

• 1372

• 17652

• 71223

• 767532

Hexadecimal Number System

Hexadecimal Number System is a base-16 numeral system used in diverse fields, especially in computing and digital electronics. It consists of 16 symbols, including numbers 0 to 9 and letters A to F, offering a compact way to represent binary-coded values. The hexadecimal number system is sometimes also represented as, ‘hex’.

An operator is a symbol that operates on a value or a variable. For example: + is an operator to perform addition.

C has a wide range of operators to perform various operations.

Example: Arithmetic Operators

// Working of arithmetic operators

#include <stdio.h>

int main()

{

    int a = 9,b = 4, c;

    c = a+b;

    printf("a+b = %d \n",c);

    c = a-b;

    printf("a-b = %d \n",c);

    c = a*b;

    printf("a*b = %d \n",c);

    c = a/b;

    printf("a/b = %d \n",c);

    c = a%b;

    printf("Remainder when a divided by b = %d \n",c);

    return 0;

}

Output

a+b = 13

a-b = 5

a*b = 36

a/b = 2

Remainder when a divided by b=1

The operators +, - and * computes addition, subtraction, and multiplication respectively as you might have expected.

In normal calculation, 9/4 = 2.25. However, the output is 2 in the program.

It is because both the variables a and b are integers. Hence, the output is also an integer. The compiler neglects the term after the decimal point and shows answer 2 instead of 2.25.

The modulo operator % computes the remainder. When a=9 is divided by b=4, the remainder is 1. The % operator can only be used with integers.

Suppose a = 5.0, b = 2.0, c = 5 and d = 2. Then in C programming,

// Either one of the operands is a floating-point number

a/b = 2.5  

a/d = 2.5  

c/b = 2.5  

// Both operands are integers

c/d = 2

C Increment and Decrement Operators

C programming has two operators increment ++ and decrement -- to change the value of an operand (constant or variable) by 1.

Increment ++ increases the value by 1 whereas decrement -- decreases the value by 1. These two operators are unary operators, meaning they only operate on a single operand.

Example: Increment and Decrement Operators

// Working of increment and decrement operators

#include <stdio.h>

int main()

{

    int a = 10, b = 100;

    float c = 10.5, d = 100.5;

    printf("++a = %d \n", ++a);

    printf("--b = %d \n", --b);

    printf("++c = %f \n", ++c);

    printf("--d = %f \n", --d);

    return 0;

}

Output

++a = 11

--b = 99

++c = 11.500000

--d = 99.500000

Here, the operators ++ and -- are used as prefixes. These two operators can also be used as postfixes like a++ and a--.

++ and -- operator as prefix and postfix

• If you use the ++ operator as a prefix like: ++var, the value of var is incremented by 1; then it returns the value.

• If you use the ++ operator as a postfix like: var++, the original value of var is returned first; then var is incremented by 1.

• The -- operator works in a similar way to the ++ operator except -- decreases the value by 1.

Example:

#include <stdio.h>

int main() {

   int var1 = 5, var2 = 5;

   // 5 is displayed

   // Then, var1 is increased to 6.

   printf("%d\n", var1++);

   // var2 is increased to 6 

   // Then, it is displayed.

   printf("%d\n", ++var2);

   return 0;

}

Example: Assignment Operators

// Working of assignment operators

#include <stdio.h>

int main()

{

    int a = 5, c;

    c = a;      // c is 5

    printf("c = %d\n", c);

    c += a;     // c is 10 

    printf("c = %d\n", c);

    c -= a;     // c is 5

    printf("c = %d\n", c);

    c *= a;     // c is 25

    printf("c = %d\n", c);

    c /= a;     // c is 5

    printf("c = %d\n", c);

    c %= a;     // c = 0

    printf("c = %d\n", c);

    return 0;

}

Output

c = 5 

c = 10 

c = 5 

c = 25 

c = 5 

c = 0

Example: Relational Operators

// Working of relational operators

#include <stdio.h>

int main()

{

    int a = 5, b = 5, c = 10;

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

    printf("%d == %d is %d \n", a, c, a == c);

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

    printf("%d > %d is %d \n", a, c, a > c);

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

    printf("%d < %d is %d \n", a, c, a < c);

    printf("%d != %d is %d \n", a, b, a != b);

    printf("%d != %d is %d \n", a, c, a != c);

    printf("%d >= %d is %d \n", a, b, a >= b);

    printf("%d >= %d is %d \n", a, c, a >= c);

    printf("%d <= %d is %d \n", a, b, a <= b);

    printf("%d <= %d is %d \n", a, c, a <= c);

    return 0;

}

Output

5 == 5 is 1

5 == 10 is 0

5 > 5 is 0

5 > 10 is 0

5 < 5 is 0

5 < 10 is 1

5 != 5 is 0

5 != 10 is 1

5 >= 5 is 1

5 >= 10 is 0

5 <= 5 is 1

5 <= 10 is 1

Example: Logical Operators

// Working of logical operators

#include <stdio.h>

int main()

{

    int a = 5, b = 5, c = 10, result;

    result = (a == b) && (c > b);

    printf("(a == b) && (c > b) is %d \n", result);

    result = (a == b) && (c < b);

    printf("(a == b) && (c < b) is %d \n", result);

    result = (a == b) || (c < b);

    printf("(a == b) || (c < b) is %d \n", result);

    result = (a != b) || (c < b);

    printf("(a != b) || (c < b) is %d \n", result);

    result = !(a != b);

    printf("!(a != b) is %d \n", result);

    result = !(a == b);

    printf("!(a == b) is %d \n", result);

    return 0;

}

Output

(a == b) && (c > b) is 1 

(a == b) && (c < b) is 0 

(a == b) || (c < b) is 1 

(a != b) || (c < b) is 0 

!(a != b) is 1 

!(a == b) is 0

Explanation of logical operator program

• (a == b) && (c > 5) evaluates to 1 because both operands (a == b) and (c > b) is 1 (true).

• (a == b) && (c < b) evaluates to 0 because operand (c < b) is 0 (false).

• (a == b) || (c < b) evaluates to 1 because (a = b) is 1 (true).

• (a != b) || (c < b) evaluates to 0 because both operand (a != b) and (c < b) are 0 (false).

• !(a != b) evaluates to 1 because operand (a != b) is 0 (false). Hence, !(a != b) is 1 (true).

• !(a == b) evaluates to 0 because (a == b) is 1 (true). Hence, !(a == b) is 0 (false).