post decrement int single pointer

In this section, you are going to learn

How to iterate Integer Arrays using ptr– ?

What is the meaning of ptr--, *ptr--, *(ptr--), *(ptr)--, (*ptr)-- ?

What is the meaning of c = ptr--, c = *ptr--, c = *(ptr--), c = *(ptr)--, c = (*ptr)-- ?

What is the difference between ptr--, *ptr--, *(ptr--), *(ptr)--, (*ptr)-- ?

What is the difference between c = ptr--, c = *ptr--, c = *(ptr--), c = *(ptr)--, c = (*ptr)-- ?

Topics of Post Decrement

• Basics of Post Decrement

• Meaning of expressions

• Summary of expressions

• Post Decrement : int pointer inside structure

• Post Decrement : Function Call

Basics of Post Decrement

• ptr - - Basic Usage

• ptr - - : Iterate and print integers of a Integer Array : Method 1

• ptr - - : Iterate and print integers of a Integer Array : Method 2

• ptr - - : Iterate and print integers of a Integer Array : Method 3

• ptr - - : Iterate and print integers of a Integer Array : Method 4

Example 1 : ptr-- : Basic Usage

• Step 1 : Define a Single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Point ptr to Single dimension array at last printable integer

int *ptr;

ptr = a + sizeof(a)/sizeof(a[0]) - 1;

• Step 3 : Decrement ptr

ptr--;

• Step 4 : Print *ptr

printf("*ptr= %d\n", *ptr);

• See full program below

#include <stdio.h>

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        int *ptr;

        ptr = a + sizeof(a)/sizeof(a[0]) - 1;

        ptr--;

        printf("*ptr= %d\n", *ptr);

        return 0;
}

• Output is as below

*ptr = 5

Example 2 : ptr-- : Iterate and print integers of a Integer Array : Method 1

• Step 1 : Define a Single Dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Point ptr to Single dimension array

int *ptr;

ptr = a + sizeof(a)/sizeof(a[0]) - 1;

• Step 3 : Print Integer Array by iterating through all integers using ptr--

for (int i = 0; i < sizeof(a)/sizeof(a[0]); i++)
{
        printf("*ptr= %d\n", *ptr);
        ptr--;
}

• See full program below

#include <stdio.h>

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        int *ptr;

        ptr = a + sizeof(a)/sizeof(a[0]) - 1;

        for (int i = 0; i < sizeof(a)/sizeof(a[0]); i++)
        {
                printf("*ptr= %d\n", *ptr);
                ptr--;
        }

        return 0;
}

• Output is as below

*ptr = 6
*ptr = 5
*ptr = 4
*ptr = 3
*ptr = 2
*ptr = 1
*ptr = 0

Example 3 : ptr-- : Iterate and print integers of a Integer Array : Method 2

• Step 1 : Define a Single Dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Point ptr to Single dimension array

int *ptr;

ptr = a + sizeof(a)/sizeof(a[0]) - 1;

• Step 3 : Print Integer Array by iterating through all integers using ptr--

while (ptr >= a)
{
        printf("*ptr= %d\n", *ptr);
        ptr--;
}

• See full program below

#include <stdio.h>

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        int *ptr;

        ptr = a + sizeof(a)/sizeof(a[0]) - 1;

        while (ptr >= a)
        {
                printf("*ptr= %d\n", *ptr);
                ptr--;
        }

        return 0;
}

• Output is as below

*ptr = 6
*ptr = 5
*ptr = 4
*ptr = 3
*ptr = 2
*ptr = 1
*ptr = 0

Example 4 : ptr-- : Iterate and print integers of a Integer Array : Method 3

• Step 1 : Define a Single Dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Point ptr to Single dimension array

int *ptr;

ptr = a + sizeof(a)/sizeof(a[0]) - 1;

• Step 3 : Print Integer Array by iterating through all integers using ptr--

while (ptr >= a)
{
        int c;

        c = *ptr--;

        printf("*ptr= %d\n", c);
}

• See full program below

#include <stdio.h>

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        int *ptr;

        ptr = a + sizeof(a)/sizeof(a[0]) - 1;

        while (ptr >= a)
        {
                int c;

                c = *ptr--;

                printf("*ptr= %d\n", c);
        }

        return 0;
}

• Output is as below

*ptr = 6
*ptr = 5
*ptr = 4
*ptr = 3
*ptr = 2
*ptr = 1
*ptr = 0

Example 5 : ptr-- : Iterate and print integers of a Integer Array : Method 4

• Step 1 : Define a Single Dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Point ptr to Single dimension array

int *ptr;

ptr = a + sizeof(a)/sizeof(a[0]) - 1;

• Step 3 : Print Integer Array by iterating through all integers using ptr--

while (ptr >= a)
{
        printf("*ptr= %d\n", *ptr--);
}

• See full program below

#include <stdio.h>

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        int *ptr;

        ptr = a + sizeof(a)/sizeof(a[0]) - 1;

        while (ptr >= a)
        {
                printf("*ptr= %d\n", *ptr--);
        }

        return 0;
}

• Output is as below

*ptr = 6
*ptr = 5
*ptr = 4
*ptr = 3
*ptr = 2
*ptr = 1
*ptr = 0

Meaning of expressions

• Meaning of ptr - - and c = ptr - -

• Meaning of *(ptr - -) and c = *(ptr - -)

• Meaning of *ptr - - and c = *ptr - -

• Meaning of *(ptr) - - and c = *(ptr) - -

• Meaning of (*ptr) - - and c = (*ptr) - -

Meaning of ptr-- and c = ptr--

• Consider statement

p = ptr--;

• There are two steps in this statement

  • Current value of ptr is assigned to p

  • ptr is decremented

• We now derived a rule

  • First Assign, then decrement

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Define a single pointer and point to array

int *ptr;

ptr = a + sizeof(a)/sizeof(a[0]) - 1;

OR

int *ptr;

ptr = &a[0] + sizeof(a)/sizeof(a[0]) - 1;

• Step 3 : Iterate and print the Integer Array

while (ptr >= a)
{
        int *p;

        p = ptr--;
        printf("*p= %d\n", *p);
}

Can you guess what is happening ?

• Let us Recall

p = ptr--;

• There are two steps in this statement

  • Current value of ptr is assigned to p

  • ptr is decremented

• We now derived a rule

  • First Assign, then decrement

• See full program below

#include <stdio.h>

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        int *ptr;

        ptr = a + sizeof(a)/sizeof(a[0]) - 1;

        while (ptr >= a)
        {
                int *p;

                p = ptr--;
                printf("*p = %d\n", *p);
        }

        return 0;
}

• Output is as below

*p = 6
*p = 5
*p = 4
*p = 3
*p = 2
*p = 1
*p = 0

Meaning of *(ptr--) and c = *(ptr--)

• Consider statement

c = *(ptr--);

• There are two steps in this statement

  • Current value of *ptr is assigned to c

  • ptr is decremented

  • *ptr is NOT decremented

• We now derived a rule

  • First Assign, then decrement

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Define a single pointer and point to array

int *ptr;

ptr = a + sizeof(a)/sizeof(a[0]) - 1;

OR

int *ptr;

ptr = &a[0] + sizeof(a)/sizeof(a[0]) - 1;

• Step 3 : Iterate and print the Integer Array

while (ptr >= a)
{
        int c;

        c = *(ptr--);
        printf("c = %d\n", c);
}

Can you guess what is happening ?

• Let us Recall

c = *(ptr--);

• There are two steps in this statement

  • Current value of *ptr is assigned to c

  • ptr is decremented

  • *ptr is NOT decremented

• We now derived a rule

  • First Assign, then decrement

• See full program below

#include <stdio.h>

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        int *ptr;

        ptr = a + sizeof(a)/sizeof(a[0]) - 1;

        while (ptr >= a)
        {
                int c;

                c = *(ptr--);
                printf("c = %d\n", c);
        }

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

Meaning of *ptr-- and c = *ptr--

• Same as *(ptr - -) and c = *(ptr - -)

• Consider statement

c = *ptr--;

• There are two steps in this statement

  • Current value of *ptr is assigned to c

  • ptr is decremented

  • *ptr is NOT decremented

• We now derived a rule

  • First Assign, then decrement

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Define a single pointer and point to array

int *ptr;

ptr = a + sizeof(a)/sizeof(a[0]) - 1;

OR

int *ptr;

ptr = &a[0] + sizeof(a)/sizeof(a[0]) - 1;

• Step 3 : Iterate and print the Integer Array

while (ptr >= a)
{
        int c;

        c = *ptr--;
        printf("c = %d\n", c);
}

Can you guess what is happening ?

• Let us Recall

c = *ptr--;

• There are two steps in this statement

  • Current value of *ptr is assigned to c

  • ptr is decremented

  • *ptr is NOT decremented

• We now derived a rule

  • First Assign, then decrement

• See full program below

#include <stdio.h>

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        int *ptr;

        ptr = a + sizeof(a)/sizeof(a[0]) - 1;

        while (ptr >= a)
        {
                int c;

                c = *ptr--;
                printf("c = %d\n", c);
        }

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

Meaning of *(ptr)-- and c = *(ptr)--

• Same as *(ptr - -) and c = *(ptr - -)

• Consider statement

c = *(ptr)--;

• There are two steps in this statement

  • Current value of *ptr is assigned to c

  • ptr is decremented

  • *ptr is NOT decremented

• We now derived a rule

  • First Assign, then decrement

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Define a single pointer and point to array

int *ptr;

ptr = a + sizeof(a)/sizeof(a[0]) - 1;

OR

int *ptr;

ptr = &a[0] + sizeof(a)/sizeof(a[0]) - 1;

• Step 3 : Iterate and print the Integer Array

while (ptr >= a)
{
        int c;

        c = *(ptr)--;
        printf("c = %d\n", c);
}

Can you guess what is happening ?

• Let us Recall

c = *(ptr)--;

• There are two steps in this statement

  • Current value of *ptr is assigned to c

  • ptr is decremented

  • *ptr is NOT decremented

• We now derived a rule

  • First Assign, then decrement

• See full program below

#include <stdio.h>

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        int *ptr;

        ptr = a + sizeof(a)/sizeof(a[0]) - 1;

        while (ptr >= a)
        {
                int c;

                c = *(ptr)--;
                printf("c = %d\n", c);
        }

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

Meaning of (*ptr)-- and c = (*ptr)--

• Consider statement

c = (*ptr)--;

• There are two steps in this statement

  • Current value of *ptr is assigned to c

  • ptr is NOT decremented

  • *ptr is decremented

• We now derived a rule

  • First Assign, then decrement

Summary of expressions

• Summary of Post Decrement expressions

Summary of Post Decrement expressions

Expression	Explanation
c = ptr–	Assign ptr to c Decrement ptr
c = *(ptr–)	Assign *ptr to c Decrement ptr DO NOT decrement *ptr
c = *ptr–	Assign *ptr to c Decrement ptr DO NOT decrement *ptr
c = *(ptr)–	Assign *ptr to c Decrement ptr DO NOT decrement *ptr
c = (*ptr)–	Assign *ptr to c DO NOT decrement ptr Decrement *ptr

Post Decrement : int pointer inside structure

• Integer pointer accessed using Structure Object

• Integer pointer accessed using Structure Single Pointer

• Integer pointer accessed using Structure Double Pointer

• Integer pointer accessed using Structure Triple Pointer

• Integer pointer accessed using Nested Structure Object

• Integer pointer accessed using Nested Structure Single Pointer

• Integer pointer accessed using Nested Structure 2 level Pointers

Integer pointer accessed using Structure Object

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Create a structure object

struct ABC abc;

• Step 3 : Point single integer pointer to single dimension array

abc.ptr =  a + sizeof(a)/sizeof(a[0]) - 1;;

• Step 4 : Iterate through single dimension array using pointer

while (abc.ptr >= a)
{
        int c;

        c = *abc.ptr--;
        printf("c = %d\n", c);
}

• See full program below

#include <stdio.h>

struct ABC
{
        int *ptr;
};

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        struct ABC abc;

        abc.ptr =  a + sizeof(a)/sizeof(a[0]) - 1;;

        while (abc.ptr >= a)
        {
                int c;

                c = *abc.ptr--;
                printf("c = %d\n", c);
        }

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

Integer pointer accessed using Structure Single Pointer

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Allocate memory for structure pointers

struct ABC *sp;

sp = malloc(sizeof(struct ABC));

• Step 3 : Point single integer pointer to single dimension array

sp->ptr =  a + sizeof(a)/sizeof(a[0]) - 1;;

• Step 4 : Iterate through single dimension array using pointer

while (sp->ptr >= a)
{
        int c;

        c = *sp->ptr--;
        printf("c = %d\n", c);
}

• Step 5 : Free memory after use

free(sp);

• See full program below

#include <stdio.h>
#include <stdlib.h>

struct ABC
{
        int *ptr;
};

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        struct ABC *sp;

        sp = malloc(sizeof(struct ABC));

        sp->ptr =  a + sizeof(a)/sizeof(a[0]) - 1;;

        while (sp->ptr >= a)
        {
                int c;

                c = *sp->ptr--;
                printf("c = %d\n", c);
        }

        free(sp);

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

Integer pointer accessed using Structure Double Pointer

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Allocate memory for structure pointers

struct ABC **dp;

dp = malloc(sizeof(struct ABC *));
*dp = malloc(sizeof(struct ABC ));

• Step 3 : Point single integer pointer to single dimension array

(*dp)->ptr =  a + sizeof(a)/sizeof(a[0]) - 1;;

• Step 4 : Iterate through single dimension array using pointer

while ((*dp)->ptr >= a)
{
        int c;

        c = *(*dp)->ptr--;
        printf("c = %d\n", c);
}

• Step 5 : Free memory after use

free(*dp);
free(dp);

• See full program below

#include <stdio.h>
#include <stdlib.h>

struct ABC
{
        int *ptr;
};

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        struct ABC **dp;

        dp = malloc(sizeof(struct ABC *));
        *dp = malloc(sizeof(struct ABC ));

        (*dp)->ptr =  a + sizeof(a)/sizeof(a[0]) - 1;;

        while ((*dp)->ptr >= a)
        {
                int c;

                c = *(*dp)->ptr--;
                printf("c = %d\n", c);
        }

        free(*dp);
        free(dp);

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

Integer pointer accessed using Structure Triple Pointer

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Allocate memory for structure pointers

struct ABC ***dp;

dp = malloc(sizeof(struct ABC **));
*dp = malloc(sizeof(struct ABC *));
**dp = malloc(sizeof(struct ABC ));

• Step 3 : Point single integer pointer to single dimension array

(**dp)->ptr =  a + sizeof(a)/sizeof(a[0]) - 1;;

• Step 4 : Iterate through single dimension array using pointer

while ((**dp)->ptr >= a)
{
        int c;

        c = *(**dp)->ptr--;
        printf("c = %d\n", c);
}

• Step 5 : Free memory after use

free(**dp);
free(*dp);
free(dp);

• See full program below

#include <stdio.h>
#include <stdlib.h>

struct ABC
{
        int *ptr;
};

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        struct ABC ***dp;

        dp = malloc(sizeof(struct ABC **));
        *dp = malloc(sizeof(struct ABC *));
        **dp = malloc(sizeof(struct ABC ));

        (**dp)->ptr =  a + sizeof(a)/sizeof(a[0]) - 1;

        while ((**dp)->ptr >= a)
        {
                int c;

                c = *(**dp)->ptr--;
                printf("c = %d\n", c);
        }

        free(**dp);
        free(*dp);
        free(dp);

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

Integer pointer accessed using Nested Structure Object

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Create a structure object

struct ABC abc;

• Step 3 : Point single integer pointer to single dimension array

abc.pqr.ptr =  a + sizeof(a)/sizeof(a[0]) - 1;;

• Step 4 : Iterate through single dimension array using pointer

while (abc.pqr.ptr >= a)
{
        int c;

        c = *abc.pqr.ptr--;
        printf("c = %d\n", c);
}

• See full program below

#include <stdio.h>

struct PQR
{
        int *ptr;
};

struct ABC
{
        struct PQR pqr;
};

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        struct ABC abc;

        abc.pqr.ptr =  a + sizeof(a)/sizeof(a[0]) - 1;;

        while (abc.pqr.ptr >= a)
        {
                int c;

                c = *abc.pqr.ptr--;
                printf("c = %d\n", c);
        }

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

Integer pointer accessed using Nested Structure Single Pointer

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Allocate memory for structure pointers

struct ABC *sp;

sp = malloc(sizeof(struct ABC));

• Step 3 : Point single integer pointer to single dimension array

sp->pqr.ptr =  a + sizeof(a)/sizeof(a[0]) - 1;

• Step 4 : Iterate through single dimension array using pointer

while (sp->pqr.ptr >= a)
{
        int c;

        c = *sp->pqr.ptr--;
        printf("c = %d\n", c);
}

• Step 5 : Free memory after use

free(sp);

• See full program below

#include <stdio.h>
#include <stdlib.h>

struct PQR
{
        int *ptr;
};

struct ABC
{
        struct PQR pqr;
};

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        struct ABC *sp;

        sp = malloc(sizeof(struct ABC));

        sp->pqr.ptr =  a + sizeof(a)/sizeof(a[0]) - 1;;

        while (sp->pqr.ptr >= a)
        {
                int c;

                c = *sp->pqr.ptr--;
                printf("c = %d\n", c);
        }

        free(sp);

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

Integer pointer accessed using Nested Structure 2 level Pointers

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Allocate memory for structure pointers

struct ABC *abc;

abc = malloc(sizeof(struct ABC));
abc->pqr = malloc(sizeof(struct PQR));

• Step 3 : Point single integer pointer to single dimension array

abc->pqr->ptr =  a + sizeof(a)/sizeof(a[0]) - 1;

• Step 4 : Iterate through single dimension array using pointer

while (abc->pqr->ptr >= a)
{
        int c;

        c = *abc->pqr->ptr--;
        printf("c = %d\n", c);
}

• Step 5 : Free memory after use

free(abc->pqr);
free(abc);

• See full program below

#include <stdio.h>
#include <stdlib.h>

struct PQR
{
        int *ptr;
};

struct ABC
{
        struct PQR *pqr;
};

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        struct ABC *abc;

        abc = malloc(sizeof(struct ABC));
        abc->pqr = malloc(sizeof(struct PQR));

        abc->pqr->ptr =  a + sizeof(a)/sizeof(a[0]) - 1;

        while (abc->pqr->ptr >= a)
        {
                int c;

                c = *abc->pqr->ptr--;
                printf("c = %d\n", c);
        }

        free(abc->pqr);
        free(abc);

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

Post Decrement : Function Call

• *ptr - - : Function Call

• ptr - - : Function Call

*ptr - - : Function Call

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Define a single pointer and point to array

int *ptr;

ptr =  a + sizeof(a)/sizeof(a[0]) - 1;

• Step 3 : Iterate array using ptr– and Pass by Value

while (ptr >= a)
{
        fun(*ptr--);
}

• Step 4 : Define a function fun which receives a integer from caller

void fun(int c)
{
        printf("c = %d\n", c);
}

Let us Recall,

• In case of *ptr--

  • Current value of *ptr is first assigned, then ptr decremented

• Hence, in this case

  • Current value of *ptr is first passed to function fun, then ptr decremented

• See full program below

#include <stdio.h>

void fun(int c)
{
        printf("c = %d\n", c);
}

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        int *ptr;

        ptr =  a + sizeof(a)/sizeof(a[0]) - 1;

        while (ptr >= a)
        {
                fun(*ptr--);
        }

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

ptr - - : Function Call

• Step 1 : Define a single dimension array

int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

• Step 2 : Define a single pointer and point to array

int *ptr;

ptr =  a + sizeof(a)/sizeof(a[0]) - 1;

• Step 3 : Iterate array using ptr– and Pass by Value

while (ptr >=a)
{
        fun(ptr--);
}

• Step 4 : Define a function fun which receives a integer pointer from caller

void fun(int *c)
{
        printf("*c = %d\n", *c);
}

Let us Recall,

• In case of ptr--

  • Current value of ptr is first assigned, then decremented

• Hence, in this case

  • Current value of ptr is first passed to function fun, then decremented

• See full program below

#include <stdio.h>

void fun(int *c)
{
        printf("*c = %d\n", *c);
}

int main(void)
{
        int a[7] = { 0, 1, 2, 3, 4, 5, 6 };

        int *ptr;

        ptr =  a + sizeof(a)/sizeof(a[0]) - 1;

        while (ptr >=a)
        {
                fun(ptr--);
        }

        return 0;
}

• Output is as below

c = 6
c = 5
c = 4
c = 3
c = 2
c = 1
c = 0

See Also

• Current Module

  • Post Decrement with Pointers

• Previous Module

  • Pre decrement with Pointers

• Other Modules

  • Basic Equations

  • Basic Arrays

  • Malloc and Pointers

  • Type-Casting and Pointers

  • Functions and Pointers

  • Memcpy and Pointers

  • Const Pointers

  • void Pointers

  • Array of Pointers

  • Function Pointers

  • Pointer to an Array

  • Pre Increment with Pointers

  • Post Increment with Pointers