C – Increment and Decrement Operators

Modify operators:

• Modify operators increase or decrease the value of variable by 1
• Operators are ++, —
• Modify operators also called unary operators (operate on single operand)

Pre-Increment	Post-Decrement	Pre-Decrement	Pos-Decrement
Example:      int a = 5;      print(++a); // 6      print(a); //6	Example:      int a = 5;      print(a++); // 5      print(a); //6	Example:      int a = 5;      print(–a); // 4      print(a); //4	Example:      int a = 5;      print(a–); // 5      print(a); //4

Expressions with modify operators evaluate as follows:

1. Pre-Increment and Pre-Decrement
2. Substitute values in expression
3. Evaluation of expression
4. Assignment
5. Post-Increment and Post-Decrement

Code snippets to understand the execution flow of Modify operators:

int main() {             int a=5;             printf(“%d\n”, ++a);             printf(“%d\n”, a);             return 0; }	int main() {             int a=5;             printf(“%d\n”, a++);             printf(“%d\n”, a);             return 0; }	int main() {             int a=5;             printf(“%d\n”, –a);             printf(“%d\n”, a);             return 0; }
int main() {             int a=5;             printf(“%d\n”, a–);             printf(“%d\n”, a);             return 0; }	int main() {             int a=5, b;             b = ++a;             printf(“a=%d\n”, a);             printf(“b=%d\n”, b);             return 0; }	int main() {             int a=5, b;             b = a++;             printf(“a=%d\n”, a);             printf(“b=%d\n”, b);             return 0; }
int main() {             int a=5, b;             b = –a;             printf(“a=%d\n”, a);             printf(“b=%d\n”, b);             return 0; }	int main() {             int a=5, b;             b = a–;             printf(“a=%d\n”, a);             printf(“b=%d\n”, b);             return 0; }	int main() {             int a=5, b;             b = ++a + ++a;             printf(“a=%d\n”, a);             printf(“b=%d\n”, b);             return 0; }
#include<stdio.h> int main() {             int a=5, b;             b = ++a + a++;             printf(“a=%d\n”, a);             printf(“b=%d\n”, b);             return 0; }	#include<stdio.h> int main() {             int a=5, b;             b = a++ + a++;             printf(“a=%d\n”, a);             printf(“b=%d\n”, b);             return 0; }	#include<stdio.h> int main() {             int a=5, b;             b = –a + –a;             printf(“a=%d\n”, a);             printf(“b=%d\n”, b);             return 0; }
#include<stdio.h> int main() {             int a=5, b;             b = –a + a–;             printf(“a=%d\n”, a);             printf(“b=%d\n”, b);             return 0; }	#include<stdio.h> int main() {             int a=5, b;             b = a– + a–;             printf(“a=%d\n”, a);             printf(“b=%d\n”, b);             return 0; }	#include<stdio.h> int main() {             int a=5, b;             b = a++ + ++a + a–;             printf(“a=%d\n”, a);             printf(“b=%d\n”, b);             return 0; }