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Printing the binary representation of an unsigned char backwards?

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-1

How exactly does this code work? I'm confused about the first for loop since binary starts at 0 and as long as it is not equal to the binary representation of the char it will increase, so then binary is 1 and so on?

unsigned char c;
int binary;

scanf("%c", &c);
getchar();

printf("The decimal representation is: %dn", c);

for (binary = 0; (1<<binary)<=c; binary++) // moving to the left
 // until binary code matches c

printf("The backwards binary representation is: ");

for (int i=0; i<binary; i++) // since we know the size
 printf("%d", ((c>>i)&1)); // 1s and 0s are shifted to right


printf("n");
return 0;

c binary bit-manipulation bitwise-operators

share|improve this question

asked Mar 22 at 0:48

Jaw Jaw

41

add a comment | 

-1

How exactly does this code work? I'm confused about the first for loop since binary starts at 0 and as long as it is not equal to the binary representation of the char it will increase, so then binary is 1 and so on?

unsigned char c;
int binary;

scanf("%c", &c);
getchar();

printf("The decimal representation is: %dn", c);

for (binary = 0; (1<<binary)<=c; binary++) // moving to the left
 // until binary code matches c

printf("The backwards binary representation is: ");

for (int i=0; i<binary; i++) // since we know the size
 printf("%d", ((c>>i)&1)); // 1s and 0s are shifted to right


printf("n");
return 0;

c binary bit-manipulation bitwise-operators

share|improve this question

asked Mar 22 at 0:48

Jaw Jaw

41

add a comment | 

How exactly does this code work? I'm confused about the first for loop since binary starts at 0 and as long as it is not equal to the binary representation of the char it will increase, so then binary is 1 and so on?

unsigned char c;
int binary;

scanf("%c", &c);
getchar();

printf("The decimal representation is: %dn", c);

for (binary = 0; (1<<binary)<=c; binary++) // moving to the left
 // until binary code matches c

printf("The backwards binary representation is: ");

for (int i=0; i<binary; i++) // since we know the size
 printf("%d", ((c>>i)&1)); // 1s and 0s are shifted to right


printf("n");
return 0;

c binary bit-manipulation bitwise-operators

share|improve this question

asked Mar 22 at 0:48

Jaw Jaw

41

scanf("%c", &c);
getchar();

printf("The decimal representation is: %dn", c);

for (binary = 0; (1<<binary)<=c; binary++) // moving to the left
 // until binary code matches c

printf("The backwards binary representation is: ");

for (int i=0; i<binary; i++) // since we know the size
 printf("%d", ((c>>i)&1)); // 1s and 0s are shifted to right


printf("n");
return 0;

share|improve this question

asked Mar 22 at 0:48

Jaw Jaw

41

share|improve this question

asked Mar 22 at 0:48

Jaw Jaw

41

asked Mar 22 at 0:48

Jaw Jaw

41

asked Mar 22 at 0:48

Jaw Jaw

41

1 Answer
1

active

oldest

votes

1

This:

for (binary = 0; (1<<binary)<=c; binary++)

simply counts how many significant bits are in the integer "c".

For instance, if "c" is 0101100 in binary, the most significant bit is the 6th from the right, and "binary" would be set to 6.

If "c" is 01 in binary, the most significant bit is the first from the right, and "binary" would be set to 1.

---

The biggest problem with this code is its almost useless comments.
If there must be comments, replace this:

/* moving to the left until binary code matches c */

with this:

/* Count number of significant bits.*/

Comments should say why the code is there, not describe how it works.

Comments like this don't serve any purpose:

/* since we know the size 1s and 0s are shift to right */

---

The second biggest problem is the variable names. "binary" is misleading. Call it "number_of_significant_bits" instead and the code almost doesn't need any comments.

share|improve this answer

answered Mar 22 at 1:14

Ray ButterworthRay Butterworth

15717

add a comment | 

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1

This:

for (binary = 0; (1<<binary)<=c; binary++)

simply counts how many significant bits are in the integer "c".

For instance, if "c" is 0101100 in binary, the most significant bit is the 6th from the right, and "binary" would be set to 6.

If "c" is 01 in binary, the most significant bit is the first from the right, and "binary" would be set to 1.

---

The biggest problem with this code is its almost useless comments.
If there must be comments, replace this:

/* moving to the left until binary code matches c */

with this:

/* Count number of significant bits.*/

Comments should say why the code is there, not describe how it works.

Comments like this don't serve any purpose:

/* since we know the size 1s and 0s are shift to right */

---

The second biggest problem is the variable names. "binary" is misleading. Call it "number_of_significant_bits" instead and the code almost doesn't need any comments.

share|improve this answer

answered Mar 22 at 1:14

Ray ButterworthRay Butterworth

15717

add a comment | 

1

This:

for (binary = 0; (1<<binary)<=c; binary++)

simply counts how many significant bits are in the integer "c".

For instance, if "c" is 0101100 in binary, the most significant bit is the 6th from the right, and "binary" would be set to 6.

If "c" is 01 in binary, the most significant bit is the first from the right, and "binary" would be set to 1.

---

The biggest problem with this code is its almost useless comments.
If there must be comments, replace this:

/* moving to the left until binary code matches c */

with this:

/* Count number of significant bits.*/

Comments should say why the code is there, not describe how it works.

Comments like this don't serve any purpose:

/* since we know the size 1s and 0s are shift to right */

---

The second biggest problem is the variable names. "binary" is misleading. Call it "number_of_significant_bits" instead and the code almost doesn't need any comments.

share|improve this answer

answered Mar 22 at 1:14

Ray ButterworthRay Butterworth

15717

add a comment | 

This:

for (binary = 0; (1<<binary)<=c; binary++)

simply counts how many significant bits are in the integer "c".

For instance, if "c" is 0101100 in binary, the most significant bit is the 6th from the right, and "binary" would be set to 6.

If "c" is 01 in binary, the most significant bit is the first from the right, and "binary" would be set to 1.

---

The biggest problem with this code is its almost useless comments.
If there must be comments, replace this:

/* moving to the left until binary code matches c */

with this:

/* Count number of significant bits.*/

Comments should say why the code is there, not describe how it works.

Comments like this don't serve any purpose:

/* since we know the size 1s and 0s are shift to right */

---

The second biggest problem is the variable names. "binary" is misleading. Call it "number_of_significant_bits" instead and the code almost doesn't need any comments.

share|improve this answer

answered Mar 22 at 1:14

Ray ButterworthRay Butterworth

15717

for (binary = 0; (1<<binary)<=c; binary++)

/* moving to the left until binary code matches c */

/* Count number of significant bits.*/

/* since we know the size 1s and 0s are shift to right */

share|improve this answer

answered Mar 22 at 1:14

Ray ButterworthRay Butterworth

15717

answered Mar 22 at 1:14

Ray ButterworthRay Butterworth

15717

answered Mar 22 at 1:14

Ray ButterworthRay Butterworth

15717