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Learn Sum, Difference, Increment, Decrement | Operators
C Basics

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Sum, Difference, Increment, Decrement

Addition Operator (+)

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

int result = 50 + 2;

You can also use variables in place of direct values.

c

Main

copy
#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;
}
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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

copy
#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;
}
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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

copy
#include <stdio.h>

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

return 0;
}
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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.

int value = 100;
value++; // Equivalent to: value += 1

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:

int value = 100;
value--; // Equivalent to: value -= 1

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

copy
#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;
}
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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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