I came across some code and it's not clear why it is casting an unsigned char * to another pointer type only to free it right after. Here are the relevant structures:
As you can see, _Edge_Message has a *msg field, but in the function below, they cast it to the other two structure types inside the case blocks of the switch statement only to free it. What is the point or advantage of doing this?
Code:
void
_edje_message_free(Edje_Message *em) {
if (em->msg) {
int i;
switch (em->type) {
Now i want to convert this into a unsigned char pointer.
unsigned char * pBMPHeaderData;
I already got the raw image data in another unsigned char buffer.
unsigned char* pRawBMPData;
Now i want to make a complete BMP image by adding the header info and raw data into a new unsigned char pointer. For this i need to convert the BITMAPINFO struct into a unsigned char *
How can i write a function that will read an "unsigned integer" into a variable of type "unsigned short int"? i can not use cin >> inside the function.. so i am looking for atleast a hint!
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 writing a class Player which has several char arrays as private fields. I am trying to write a method which returns an array as a pointer, but doesn't alter the array in any way, thus the const.
Here is a snippet:
Code: class Player { private: char state[MAX_STATE_CHAR + ONE_VALUE]; int rating; char last[MAX_NAME_CHAR + ONE_VALUE]; char first[MAX_NAME_CHAR + ONE_VALUE]; int groupNumber = NEG_ONE; public: char * GetFirst() const { return first; }
Visual studio is saying that the return type doesn't match.
I find type casting to be very hard to grasp, I am not sure why. I understand how it works I suppose, but I find it hard to grasp why it would be needed in programming. So my question is, how often is type casting used in general programs? Is there an easier way I could be trying to teach myself about it? I am just using the tutorials provided by this site.
I'm writing a small piece of code that increments through a string of numbers. For every 5 numbers a product is produced. However i'm having an issue understanding an error that keeps occurring.
if you look at the code i've got a string with 5 numbers 1-5 for testing. As the loop increments through the string it takes the first 5 characters and converts them to integers and then a product is returned. The issue is that instead of storing the single letter at position J its storing some combination from the string and as a result gives me a huge product. I tried debugging. I checked what the string[j] value was with a simple cout << and it returned the right number. I even returned the char value before it was converted into an integer and it was the right number.
This code i made, utilizing the type casting construct, isn't outputting what i wanted. The output for 'Dollars' and 'Cents' are returning '0' for both. instead all i want it to do is seperate the two. for example changing the float value of amount to an integer, giving a dollar value.
Goal: To allocate some memory as a char*, read in some binary data, re-interpret it as a float* and then free the memory.
My code looks like:
void someFunction(float* &result) { char * tmp = new char[1000]; //...Fill the char buffer here... result = (float*)tmp; //Reinterpret binary data as floats
[Code] ....
Is the cast back to char* necessary on the red line (or could I have validly left it as float*)? Would it be different if I had written char * tmp = (char*)malloc(sizeof(char)*1000); on the blue line (and correspondingly used free (char*)floatData on the red line?
Looking for extended unsigned integer class, that has custom lenght?
The reason i am asking is because i need an extremely large integer number, in fact one that has no theoretical limit(or at least an extremely large one).
I 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++)
How do you use char instead of unsigned to calculate numbers? This is using char only and nothing else.
Step 1: I ask the user to enter a number. Step 2: User enters a number. Step 3: Number user entered is going to be that number squared or cubed or w/e.
For example; "Enter a number: " 3 " Number you entered multiplied four times: " 81 (Since (3)*(3)*(3)*(3) = 81)
Another example; "Enter a number: " 5 " Number you entered multiplied four times: " 625 (Since (5)*(5)*(5)*(5) = 625)
Code: Char num; cout << "Enter a number"; cin >> num; cout << "Number you entered multiplied four times: " << (num)*(num)*(num)*(num) << endl;
The characters show up in the list box as short unreadable characters. like it is chopped.
If i change to : Sendmessage(hndl, listboxupdate,0 , (LPARAM)&buf[15]);
Then I can see readable valid strings of up to 50 characters and then empty unreadable characters afterwards. I tried all kinds of things , including using CString, still did not work.
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 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 ..
how is the best way to free unsigned pointer array allocated with cmallc?
Code:
uint8_t *buf; buf = cs_calloc(ca->len + 13);
i do like this , but i know this is not quite right , since i got compile warning passing argument 1 of ‘free’ makes pointer from integer without a cast
Code:
for (i = 0; i < ca->len + 13; i++) { free(buf[i]); buf[i] = NULL; }
free(buf); do i need to free each element of array like above?
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.
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) {
