Sum, Difference, Increment, Decrement

Addition Operator (+)

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

You can also use variables in place of direct values.

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.

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.

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.

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:

Pre vs. Post Increment

Increment and decrement operators come in two forms:

prefix (++a);
postfix (a++).

The distinction lies in the values they return:

Operator	Usage	Description
`++`	`a++`	Increments `a` by 1 but returns its original value
`++`	`++a`	Increments `a` by 1 and returns its incremented value
`--`	`--a`	Decreases `a` by 1 and returns its decremented value
`--`	`a--`	Decreases `a` by 1 but returns its original value

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;
}

Everything was clear?

Section 3. Chapter 2