I need fastest method to reverse order of bytes in my char array.
For example i have:
unsigned char buf[8];
// consider data stored in buf is 88 77 66 55 44 33 22 11
// how to reverse it to: 11 22 33 44 55 66 77 88
// currently i can do it by equal assignment , i make another buf like:
unsigned char buf_ok[8];
[Code] ....
// This does reverse the bytes as i want but its very slow , i am looking for fast method ..
The program should store a character array in reverse order then display the reversed array. I have also included in the code that will display the actual characters into the array as it loops through. So I know the characters are being stored, but why doesn't it display the entire string when I call it?
Code:
#include<stdio.h>
int main(){
char str[50];
char rev[50];
printf("Enter Desired Text: ");
scanf ("%[^
[Code] ....
Is it just my compiler?
I'm confused about the actual value of 8 bytes for unsigned integers.
The below code suggests the value is 13217906525252912201:
#include <stdio.h>
#include <inttypes.h>
typedef uint64_t byte_int_t;
int main(void){
byte_int_t t;
printf("%" PRIu64 "
", t);
}
./runprogram
13217906525252912201
However, when I use a calculator, I get a different value: 2^64= 1.8446744e+19
So I was wondering is this really 8 bytes? So I try below test and it produces 8, as expected:
#include <stdio.h>
#include <inttypes.h>
typedef uint64_t byte_int_t;
int main(void) {
byte_int_t t;
printf("%u
", sizeof(t));
return 0;
}
So why does C and my calculator provide two different results?
I do not understand how I can implement this.If fread != to at least 8 bytes then do THIS: printf (" your file is near the end of file", fread result);
View 8 Replies View RelatedI am having some trouble performing this. I am not sure, if my unsigned char arrays are null terminated, but I don't think so. Here is my code: They are supposed to be byte arrays of size 16.
int setkey(unsigned char* ky) {
printf("INSIDE POLY-DEL ... key byte array passed in HEX:
");
int i;
for (i = 0; i < (int)16; i++)
[Code] .....
i wish to generate all possible key combinations ranging:
HEX: "0F FF FF FF FF FF FF FF" TO HEX: FF FF FF FF FF FF FF FF
i also test each key after incrementing by 1, for test i want the key to be a an unsigned char[8]
key start rang and end range can be initialize/declare in any format.
Problem is if :
unsigned char key[] = {0x0F,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
then i can not increment this key by +1 , though if i initialize this key in decimal as:
unsigned long long key = 1152921504606846975;
then i can increment the key in for loop by key++ but then i cant convert it back into unsigned char array
i want to achieve something like this :
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
unsigned char key[] = {0x0F,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
int main()
{
[code]...
In my programer i also have function that test each key but key has to be unsigned char...
I'm trying to use a priority queue sorting in reverse order to take a vector or 2d array. The problem is that I want to sort by the vector/array cell value but keep the reference to the vector/array index of the value. I don't know quite howto keep them both related so when I pop. I can find the corresponding cell.
priority_queue<int, vector<int>, greater<int> > Open;
Using the array to accept 10 testscore. Calculate and print the highest, lowest, fifth test score entered and all the test score entered in reverse order.
How i would get it to print the highest,and lowest and in reverse order. I'm confused as to what to do...
I have an embedded microcontroller system communicating with a similar system by radio. The api for the radio requires data to be transmitted as an unsigned char array. It will always transmit a positive integer in the range 0 to 255.When I receive the data I am having difficult in extracting this positive integer.
Code:
unsigned char rxData[4]={'1','2','3',''};
int inVal=0;
//want to assign inVal whatever number was transmitted
E.g. 123
I've been at this for a week and have tried at least 10 different approaches including the use of the atoi(), copying the absolute value of each element of rxData into another char array, reinterpret_cast, and others.
I have the following code which attempts to assign a u_int8 array of 256 to an unsigned char[256]:
Code:
unsigned char testData[256]=pSample->data;
I get the compilation error:
error C2440: 'initializing' : cannot convert from 'const uint8_t [256]' to 'unsigned char [256]'
What is the safe way to cast or convert here?
I'm having a pretty weird problem. I've created an unsigned char array for an image buffer:
buffer_rgb = new unsigned char[_w * _h * 3];
memset(buffer_rgb, 0x0, sizeof(unsigned char)* _w * _h * 3);
And I add pixel color values to it like so:
buffer_rgb[i] = ((unsigned char)(col[0] * 255));
buffer_rgb[i + 1] = ((unsigned char)(col[1] * 255));
buffer_rgb[i + 2] = ((unsigned char)(col[2] * 255));
Where col is a 'vec4' struct with a double[4] with values between 0 and 1 (this is checked and clamped elsewhere, and the output is safely within bounds). This is basically used to store rgb and intensity values.
Now, when I add a constant integer as a pixel value, i.e.:
buffer_rgb[i] = ((unsigned char)255;
Everything works as it should. However, when I use the above code, where col is different for every sample sent to the buffer, the resulting image becomes skewed in a weird way, as if the buffer writing is becoming offset as it goes.
These two images illustrate the problem:
tomsvilans.com/temp/140803_render_skew.png
tomsvilans.com/temp/140803_render_noskew.png
You can see in the 'noskew' image all pixels are the same value, from just using an unchanging int to set them. It seems to work with any value between 0-255 but fails only when this value is pulled from my changing col array.
Whole function is here:
// adds sample to pixel. coordinates must be between (-1,1)
void Frame::addSample(vec4 col, double contrib, double x, double y) {
if (x < -1 || x >= 1 || y < -_aaspect || y >= _aaspect) {
[Code] .....
unsigned char key[32];
139 unsigned char rfseed[32];
173 f = fopen("/dev/urandom","rb");
174 fread(key,1,32,f);
175 fread(rfseed,1,32,f);
I am having problems copying outputs of the above code into other unsigned char other[32]. I need to keep the output of dev/urandom for backup. But, when I try to assign the values by memcpy(other, key, 32), the values do not match. The same problem happens by assigning values index by index in a loop.
I am trying to assign the integer value to unsigned char array. But it is not storing the integer values. It prints the ascii values. Here the code snippet
Code: uchar uc[100];
for(i=0;i<100;i++)
{
uc[i] = i;
}
The values which are stored in uc[] is ascii values.I need the integer values to be stored in uc[]. I tried to do it with sprintf. but the output is not as expected. if I print the uc[i] it should diplay the value as 0,1,2....99.
How to print a string in reverse order(for example: "today is Wednesday " to "Wednesday is today"). My professor said we should begin with a null string and build it one word at a time.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int nwords(string);
[Code] .....
I need to do program where i will input sentence and then output it in reverse order. Example: today is Monday ----> Monday is today. So I have this:
#include <iostream>
#include <cstring>
using namespace std;
int main() {
char niz[20],niz2[20];
int lenght,k=0;
[Code] ....
For output I only get one word of sentence,example: Monday is today--->today and nothing else.
I have two vectors of float that I need to sort in reverse order. reverse() seems to work for one of them, but not the other. I have toggled between sort() and reverse(). for one vector, the expected behavior is seen and the order reverses. For the other, there is no change in order.
This is very simple code, so it's hard to imagine what is going wrong.
Code:
vector<float> vec1, vec2;
vec1[0] = 14.1102; vec1[1] = 14.1145;
vec2[0] = 15.8508; vec2[1] = 26.0842;
sort( vec1.begin(), vec1.end() );
sort( vec2.begin(), vec2.end() );
[Code] ......
Printout is,
Code:
vector 1 sort
14.1102
14.1145
vector 2 sort
15.8508
26.0842
vector 1 reverse
14.1102
14.1145
vector 2 reverse
26.0842
15.8508
You can see that the order of the first vector did not change. Am I right in suspecting that the numbers are too similar for what ever method reverse() uses to determine the difference between values?
works fine without the for loop.... if i use for loop...it doesnt give the output...
Code: #include<iostream>
#include<conio.h>
#include<fstream>
[Code]....
The next step for my project is to take data from a file, and create a new file with the same data, but in reverse order. If a file has the following values:
1
2
3
4
5
The program should create a new file with the following values:
5
4
3
2
1
Seems pretty straight forward, yet I am hitting a snag when I try to compile my program:
Code:
#include <stdio.h>
#include <assert.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
[Code] ....
The following errors occur when I try to compile the fore mentioned code:
intrev.c: In function 'main':
intrev.c:25: warning: unused variable 'out'
intrev.c: At top level:
intrev.c:39: error: expected identifier or '(' before 'while'
[Code] .....
Now I am not concerned with "unused variable 'out'" as it is used, just in a for loop. Is this a problem?
I'm not entirely sure why it's giving me the error at line 39. I've gone over this a couple times and it doesn't look like I've missed any methods which need to be closed. Maybe I've missed something?
I'm also not sure why I am getting an error when I try to close the opened files. I've done this before in the same manner, but without errors. Not sure why I am now, but my guess is that it has something to do with the error on line 39.
I was trying to reverse a linklist in reverse direction using the recursion. I was able to reverse n - 1 element but it is not printing the first one. Below is my code.
Code:
typedef struct linklist {
int data;
linklist *next;
};
void add(int data,linklist **node) {
[code]....
This is happening since recursion is starting from second node, which is due to reason not printing the first one when recursion print values from stack once
node != NULL
Condition is met.
Currently I am using below statement for printing the first element;
reverse_recur(node);
printf("
Print In Reverse Order
%d
",node->data);
Need to correct the errors. i've done so far.
#include<iostream>
#include<fstream>
#include<cstdlib>
#include<iomanip>
using namespace std;
int main() {
ifstream fin; char ch; int size=0;
[Code]...
I am trying to write a program that takes a sentence and reverses the word order.
For instance This is a Bird would become Bird a is This
Code :
#include <stdio.h>
#include <string.h>
#include <ctype.h>
int main (void) {
char input_buffer[1024];
char middle[1024];
[Code] ....
1. Construct a class diagram that can be used to represent food items. A type of food can be classified as basic or prepared. Basic food items can be further classified as meat, fruit, veg or Grain. The services provide by the class should be the ability to enter data for new food, to change data for food and to display existing data about food.
using this class definition write a main program to include a simple menu that offers the following choices:
1. Add food
2. Modify Food
3. Delete Food
4. Exit this menu
2. Read a list of numbers from a file and then print them out in reverse order. State whether the list is palindromic or not.
I have used the following code to write and read wchar_t bytes from a disk file:
Code:
int WriteBytesW(wchar_t * wcp, int nsz, wchar_t * wcfilepath) {
wfstream wf;
codecvt_utf16<wchar_t, 0x10ffff, little_endian> ccvt(1);
locale wloc(wf.getloc(), &ccvt);
wf.imbue(wloc);
[Code] ....
Output:
save bytes succeeded
1234 5678 9ABC EF12 ABCD FE21 DCBA 1F2A EFFF 02FF
read bytes succeeded
nsz =: 20
Now, if wbuf[8] = 0xefff; is replaced by wbuf[8] = 0xffff;
Output:
save bytes succeeded
1234 5678 9ABC EF12 ABCD FE21 DCBA 1F2A 02FF
read bytes succeeded
nsz =: 18
Obviously, the 0xffff wbyte is not read. WHY ?
This presents a significant problem when attempting to read ALL wbytes from a file.
How do I print an unsigned char in c++? E.g.
unsigned char a[100] = "acdef";
wprintf(L"a is %u
", a);
wcout << "a is " << a << endl;
gives
a is 2880488
a is 002BF3E8
and not
a is acdef
a is acdef
??
what is the difference between unsigned char and char?
Write a for loop statement to print the numbers from 1 to 10 in reverse order separated by star :
10*9*8*7*6*5*4*3*2*1
i try to do it but it show me like this :
10*9*8*7*6*5*4*3*2*1*
how do i write to show me like the first one ?
Implement a recursive function named void printBack(DoublyLinkedNode<T>* node) for the class DoublyLinkedCircularList which will print out the elements in the list from back to front. The function is initially called with the first node in the list. You may not make use of the previous(prev) links
This is my solution where I got 2 out of a possible 3 marks:
template<class T>
void DoublyLinkedCircularList<T> :: printBack(DoublyLinkedNode<T>* node) {
if(node->next == NULL) //Correct- 1 mark
return 0;
else
printBack(node->next); //Correct - 1 mark
cout << current-> element << " ";
}