# Increment/Decrement Operator

## Pre/Post Increment/Decrement Operator

```c
#include<stdio.h>
int main(){
    int a = 10;
    int *p = &a;
    
    (*p)++; //a++;
    printf("%d\n",*p);
    
    ++(*p); //++a;
    printf("%d\n",*p);
    
    (*p)--; //a--;
    printf("%d\n",*p);
    
    --(*p); //--a;
    printf("%d\n",*p);

    return 0;
}
```

```c
#include <stdio.h>
int main() {
    int a = 10;
    
    printf("%d %d %d\n", a, a, a);//10 10 10 //10
    printf("%d %d %d\n", a++, a++, a++); //12 11 10 //13
    printf("%d %d %d\n", ++a, ++a, ++a); //16 16 16 //16
    printf("%d %d %d\n", a++, ++a, a++); //18 19 16 //19
    printf("%d %d %d\n", ++a, a++, ++a); //22 20 22 //22
    
    return 0;
}
```

```c
#include <stdio.h>
int main() {
    int a = 10;
    int *b = &a;
    
    printf("%d %d %d\n", a, a, a);       //10 10 10 //10
    printf("%d %d %d\n", a++, a++, a++); //12 11 10 //13
    printf("%d %d %d\n", ++a, ++a, ++a); //16 15 14 //16
    printf("%d %d %d\n", a++, ++a, a++); //18 18 16 //19
    printf("%d %d %d\n", ++a, a++, ++a); //22 20 20 //22
    
    return 0;
}
```

```c
include <stdio.h>
int main() {
    int a = 10;
    int *b = &a;
    int **c = &b;
    
    printf("%d %d %d\n", a, a, a);       //10 10 10 //10
    printf("%d %d %d\n", a++, a++, a++); //12 11 10 //13
    printf("%d %d %d\n", ++a, ++a, ++a); //16 15 14 //16
    printf("%d %d %d\n", a++, ++a, a++); //18 18 16 //19
    printf("%d %d %d\n", ++a, a++, ++a); //22 20 20 //22
    
    return 0;
}
```

```c
#include <stdio.h>
int main() {
    int a = 10;
    int *b = &a;
    int **c = &b;
    
    printf("%d %d %d\n", a, *b, **c);//10 10 10 //10
    printf("%d %d %d\n", ++a, ++a, ++a);//13 12 11 //13
    printf("%d %d %d\n", ++a, ++(*b), ++(**c));//16 15 14 //16
    printf("%d %d %d\n", a++, (*b)++, (**c)++);//18 17 16 //19
    printf("%d %d %d\n", a++, ++(*b), (**c)++);//21 21 19 //22
    printf("%d %d %d\n", ++a, (*b)++, ++(**c));//25 23 23 //25
    
    return 0;
}
```

```c
#include <stdio.h>
int main() {
    int a = 5, x = 0;
    int *p = &a;
    
    a = 5;
    x = a++ + a++ + a++ + a++;
    //  5   + 6   + 7   + 8    
    printf("X = %d \tA=%d\n", x, a); //X = 26 	A=9
    
    a = 5;
    x = ++a + ++a + ++a + ++a;
    //    6 +   7 +   8 +   9
    printf("X = %d \tA=%d\n", x, a); //X = 30 	A=9
    
    a = 5;
    x = ++a + a++ * ++a + ++a;
    //    6 + 6   *   8 *   9
    printf("X = %d \tA=%d\n", x, a); //X = 63 	A=9
    
    a = 5;
    x = ++a + a++ - a++ * ++a;
    //    6 + 6   - 7   *   9
    printf("X = %d \tA=%d\n", x, a); //X = -51 	A=9
    
    a = 5;
    x = ++a + a++ * ++a * ++a;
    //    6 + 6   *   8 *   9
    printf("X = %d \tA=%d\n", x, a); //X = 438 	A=9

    return 0;
}
```

### Some Invalid Increment/Decrement Operations

```c
#include<stdio.h>
int main(){
    int a = 10;
    int *p = &a;
    
    *p++; // Invalid Operation, precedence of "++" is heigher than "*"
    //(*p)++; //Recommended Expression
    printf("%d\n",*p);
    
    ++*p; // Valid Operation, But Not Recommended
    //++(*p); //Recommended Expression
    printf("%d\n",*p);
    
    *p--; // Invalid Operation, precedence of "--" is heigher than "*"
    //(*p)--; //Recommended Expression
    printf("%d\n",*p);
    
    --*p; // Valid Operation, But Not Recommended
    //--(*p); //Recommended Expression
    printf("%d\n",*p);

    return 0;
}
```

```c
#include<stdio.h>
int main(){
    int a = 10;
    int *p = &a;

    p++; // Invalid Operation, Increment the value of "p" (Memory Address)
    printf("%d\n",*p);

    return 0;
}
```


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