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C Basics
course content

Course Content

C Basics

C Basics

1. Introduction
Structure of the C-ProgramEssentials of C ProgramHow to Run the Program?
2. Data
DataVariablesPrintfIntroduction to ArraysTwo Dimensional ArraysChar and StringSizeofPrintf PracticeSizeof Practice
3. Operators
Assignment, Comparison, Not Equal ToSum, Difference, Increment, DecrementMultiplication, Division and ModuloComparison OperatorsComparison Operators PracticeLogical OperatorsLogical Operators Practice
4. Control Statements
If-else Operatorif-else Operator PracticeTernary OperatorSwitch, BreakWhile, Do-WhileFor, ContinueFor Loop Practice
5. Functions
Structure of the FunctionDeclaration, Type and ReturnArgumentsPassing ArgumentsHeader, Prototypes Void, Recursion
6. Pointers
Pointers are around UsReferences and DereferencesPointersMalloc and FreeFunctions, Arrays and Two PointersVoid

book
Sum, Difference, Increment, Decrement

Addition Operator (+)

The + operator adds the values on either side of it.

c

You can also use variables in place of direct values.

c

Main

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#include <stdio.h>

int main()
{
	int carsSold_2022 = 12;
	int carsSold_2023 = 45;

	int carsSold = carsSold_2022 + carsSold_2023;

	printf("Cars sold in two years: %d", carsSold);

	return 0;
}

Note

While some programming languages allow you to concatenate strings using the + operator, like "Hell" + "o" = "Hello", C does not.

Subtraction Operator (-)

The subtraction operator, -, calculates the difference between the values on either side of it.

c

Main

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#include <stdio.h>

int main()
{
	int carsSold_2022_2023 = 200;
	int carsSold_2023 = 57;

	int carsSold_2022 = carsSold_2022_2023 - carsSold_2023;

	printf("Cars sold in 2022: %d", carsSold_2022);

	return 0;
}

You can also use the - sign to convert positive values to their negative counterparts.

c

Main

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#include <stdio.h>

int main()
{
	int value = 100;
	
	printf("Negative value: %d", -value);

	return 0;
}

Increment Operator (++)

The increment operator, ++, was introduced to simplify code readability.

c

This operator adds 1 to a value, and it's commonly used in loops. The example above illustrates the most basic use of the operator.

Decrement Operator (--)

Conversely, the decrement operator, --, subtracts 1 from a value:

c

Pre vs. Post Increment

Increment and decrement operators come in two forms:

  • prefix (++a);
  • postfix (a++).

The distinction lies in the values they return:

OperatorUsageDescription
++a++Increments a by 1 but returns its original value
++++aIncrements a by 1 and returns its incremented value
----aDecreases a by 1 and returns its decremented value
--a--Decreases a by 1 but returns its original value
c

Main

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#include <stdio.h>

int main() 
{
	int a = 5, b = 5;

	// a is increased to 6 
	// Then, it is displayed.
	printf("Prefix form a: %d\n", ++a);
	printf("a =  %d\n", a);

	// 5 is displayed
	// Then, b is increased to 6.
	printf("Postfix form b: %d\n", b++);
	printf("b =  %d\n", b);

	return 0;
}
question mark

If b equals 7, what b++ equals to?

Select the correct answer

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Section 3. Chapter 2
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