C Programming Expressions and Operators

C - Programming

• Learning and Development session on Tuesday, November 3, 2020.

Expressions and Operators

• Expressions consist of at least one operand and zero or more operators.
• Operands are constants, variables, or function calls that return values.
• Example expression: 47, 2 + 2, cosine(3.14159). This last example implies a floating-point result.
• Parentheses group subexpressions, for example: (2 * (3 + 10) - (2 * 6)).

Operators

• C operators are categorized as:
  • Unary operators
  • Binary operators
  • Ternary operators

Types of Operators

• Unary: [+ ,- ,! ,~ ,++ ,-- ,(type) *, & ,sizeof]
• Arithmetic: [* , / , + , -]
• Relational: [ <, >, ==, !=, <=, >=]
• Logical: [&&, ||, !]
• Bitwise: [ <<, >>, ^, &, |, ~]
• Ternary/Conditional: [?:]
• Assignment: [ =, +=, -=, *=, /=, %=, >>=, <<=, &=, ^=, |= ]

Pre-incrementing

• Example: #include <stdio.h>
• int iNum = 10;
• printf("iNum is: %d\n", ++iNum);
• Output: iNum is: 11

Post-incrementing

• Example: #include <stdio.h>
• int iNum = 10;
• printf("iNum is: %d\n", iNum++);
• Output: iNum is: 10

Example Output of Pre- and Post-incrementing

• Example code demonstrates pre- and post-increment operations.
• Shows the sequence and result of ++, --, ++, and --.

Program to find Area of triangle

• Example program calculates the area of a triangle given base and height.
• Formula used: area = 1 / 2.0 * base * height.

Program to find Area of Circle

• Example program calculates the area of a circle given its radius.
• Formula used: area = π * radius^2. Uses math.h for the pow function

What is the output? (Swap two numbers in C)

• Example C code snippet to swap two numbers. Demonstrates a method of swapping using arithmetic operations and variable assignment

Relational Operators

• Table presents the relational operators in C, highlighting symbols and corresponding questions (e.g., "Is operand 1 equal to operand 2?") and examples (e.g., x == y).

Relational Operator Examples

• Defines conditions and output for relational operators, including evaluations of true or false conditions in C expressions.

Logical Operators - AND (&&)

• Logical AND operators evaluate two expressions to produce a true or false result. The second operand is not evaluated if the first is false.

Logical Operators - OR (||)

• Logical OR operators evaluate two expressions to produce a true or false result.  The second expression isn't evaluated if the first is true.

Logical Operators - NOT (!)

• The NOT operator converts a true expression to false and vice versa.

Compound Assignment Operators

• Shortcut operators combining assignment with mathematical operations (e.g., x *= y; is equivalent to x = x * y;).

The Conditional Operator

• The conditional operator (ternary) uses the syntax exp1 ? exp2 : exp3.
• exp1 is evaluated; if true, exp2 is returned; otherwise, exp3 is returned.

Max 3 Using Ternary Operator

• A practical example demonstrating how to find the greatest among three numbers using the ternary operator in C.

The Comma Operator

• The comma operator evaluates expressions from left to right, and the final result is what the right most expression evaluates to.

Bitwise Operators

• C provides bitwise operators for performing operations on the individual bits of integers. (AND, OR, XOR, bitwise NOT etc, left bit shift, right bit shift)

Following are interesting facts about bitwise operators

• Left-shift and right-shift operators should not be used with negative numbers.
• Shifting a number beyond the size of the integer results in undefined behavior.

Example of bitwise operator use

• An example program demonstrates the use of bitwise operators and their associated outputs.

Precedence and Order of Evaluation

• Table showing the order of operator precedence along with associativity in C, which defines operations evaluation order.

Type Cast

• A type cast explicitly converts a variable's type in C.
• Includes examples of data conversions.

Statements

• Statements in C programs perform actions and control program flow.
• Examples include assignment, function calls, and other statements needed to complete or execute functions in a program. Trivial statements, like x+5; will only execute or register the operation, and nothing substantial happens unless there are side effects, like executing the results of the calculation

Expression Statements

• Expression statements are typically only useful when performing actions, like storing the value of an expression or calling a function.