Search Results

Search found 6241 results on 250 pages for 'unsigned integer'.

Page 152/250 | < Previous Page | 148 149 150 151 152 153 154 155 156 157 158 159  | Next Page >

  • How to default-initialize local variables of built-in types in C++?

    - by sharptooth
    How do I default-initialize a local variable of primitive type in C++? For example if a have a typedef: typedef unsigned char boolean;//that's Microsoft RPC runtime typedef I'd like to change the following line: boolean variable = 0; //initialize to some value to ensure reproduceable behavior retrieveValue( &variable ); // do actual job into something that would automagically default-initialize the variable - I don't need to assign a specific value to it, but instead I only need it to be intialized to the same value each time the program runs - the same stuff as with a constructor initializer list where I can have: struct Struct { int Value; Struct() : Value() {} }; and the Struct::Value will be default-initialized to the same value every time an instance is cinstructed, but I never write the actual value in the code. How can I get the same behavior for local variables?

    Read the article

  • C++ Structure within itself?

    - by Douglas
    I've been trying to port this code to python, but there is something I do not quite understand in C++ (I do know a bit of C++ but this is beyond me): typedef struct huffnode_s { struct huffnode_s *zero; struct huffnode_s *one; unsigned char val; float freq; } huffnode_t; What I don't get is how huffnode_s can be within itself, I've never seen this before and don't quite understand it. What does this mean, and if someone can, what would be the python equivalent?

    Read the article

  • Why MySQL multiple-column index is overpopulated?

    - by actual
    Consider following MySQL table: CREATE TABLE `log` ( `what` enum('add', 'edit', 'remove') CHARACTER SET ascii COLLATE ascii_bin NOT NULL, `with` int(10) unsigned NOT NULL, KEY `with_what` (`with`,`what`) ) ENGINE=InnoDB; INSERT INTO `log` (`what`, `with`) VALUES ('add', 1), ('edit', 1), ('add', 2), ('remove', 2); As I understand, with_what index must have 2 unique entries on its first with level and 3 unique entries in what "subindex". But MySQL reports 4 unique entries for each level. In other words, number of unique elements for each level is always equal to number of rows in log table. Is that a bug, a feature or my misunderstanding?

    Read the article

  • Logical value of an assignment in C

    - by Andy Shulman
    while (curr_data[1] != (unsigned int)NULL && ((curr_ptr = (void*)curr_data[1]) || 1)) Two part question. What will (curr_ptr = (void*)curr_data[1]) evaluate to, logically. TRUE? Also, I know its rather hack-ish, but is the while statement legal C? I would have to go through great contortions to put the assignment elsewhere in the code, so I'd be really nice if I could leave it there, but if it's so egregious that it makes everyone's eyeballs burst into flames, I'll change it.

    Read the article

  • iphone getting hours/min/seconds app crashes.

    - by coure06
    i have this code in my overridden drawRect method NSDate *date = [NSDate date]; NSCalendar *calendar = [NSCalendar currentCalendar]; unsigned int unitFlags = NSHourCalendarUnit|NSMinuteCalendarUnit|NSSecondCalendarUnit; NSDateComponents *comp = [calendar components:unitFlags fromDate:date]; NSInteger h = [comp hour]; NSInteger m = [comp minute]; NSInteger s = [comp second]; NSLog(@"%i,%i,%i", h,m,s); NSLog(@"test"); [date release]; [calendar release]; [comp release]; I am calling drawRect using setNeedsDisplay from my custom method (timer based after each 1 secon). It runs only once and then app exit automatically. If i comment out all the code and just write NSLog(@"test"); then application works ok, it logs "test" after each 1 sec.

    Read the article

  • Please explain syntax rules and scope for "typedef"

    - by unknown google user
    What are the rules? OTOH the simple case seems to imply the new type is the last thing on a line. Like here Uchar is the new type. typedef unsigned char Uchar; But a function pointer is completely different. Here the new type is pFunc: typedef int (*pFunc) (int); I can't think of any other examples offhand but I have come across some very confusing usages. So are there rules or are people just suppose to know from experience that this is how it is done because they have seen it done this way before? ALSO: What is the scope of a typedef. Thanks to everyone.

    Read the article

  • What could possibly cause this error(when declaring an object inside a class) ? //noobie question

    - by M4design
    I'm battling with this assignment :) I've got two classes: Ocean and Grid. When I declare an object of the Grid inside the Ocean: unsigned int sharkCount; Grid grid; The compiler/complainer says: error C2146: syntax error : missing ';' before identifier 'grid' Can you possibly predict what produces this error with the limited info' I provided? It seems that as if the Ocean doesn't like the Grid class. Could this be because of the poor implementation of the grid class. BTW the Grid has a default constructor. Yet the error happens in compiling time!. Thanks. EDIT: They're each in separate header file, and I've included the Grid.h in the Ocean.h.

    Read the article

  • How to I count key collisions when using boost::unordered_map?

    - by Nikhil
    I have a data structure with 15 unsigned longs, I have defined a hash function using hash_combine as follows: friend std::size_t hash_value(const TUPLE15& given) { std::size_t seed = 0; boost::hash_combine(seed, val1); boost::hash_combine(seed, val2); ... return seed; } I insert a large number of values into a boost::unordered_map but the performance is not good enough. Probably, I could do better with an alternative hashing function. To confirm this, I need to check how many collisions I am getting. How do I do this?

    Read the article

  • Where does output of print in kernel go?

    - by apoorv020
    I am debugging a driver for linux (specifically ubuntu server 9.04), and there are several printf statements in the code. Where can I view the output of these statements? EDIT1: What i'm trying to do is write to kernel using the proc file-system. The print code is static int proc_fractel_config_write(struct file *file, const char *argbuf, unsigned long count, void *data) { printk(KERN_DEBUG "writing fractel config\n"); ... In kern.log when I see the following message when i try to overwrite the file /proc/net/madwifi/ath1/fractel_config (with varying time of course). [ 8671.924873] proc write [ 8671.924919] Any explainations?

    Read the article

  • technique for how to debug macros in C

    - by Dervin Thunk
    Hi. So I have the (mostly vilified) #define MAX( a, b ) ( ((a) > (b)) ? (a) : (b) ) somewhere in a program (yes, yes, I know). At some point in the code there is a comparison X>-1?, where X is (as far as I can tell) a (signed) integer. The line is j += MAX(bmGs[i], bmBc[(int)y[i + j]] - m + 1 + i);, where y here is a char*. Not necessarily surprisingly, I find that the macro is returning -1 as the larger number (I'm guessing too long a number for int or an unsigned issue, but I can't find it). I would like to know techniques you guys may have for finding these kinds of errors. Notice that I'm not asking for programming advice about whether or not to use that macro, I'm sure folks are dying to tell me I should refrain from things like that, but the question is going somewhere else. Thanks.

    Read the article

  • How i store the images pixels in matrix form?

    - by Rajendra Bhole
    Hi, I developing an application in which the pixelize image i want to be store in matrix format. The code is as follows. struct pixel { //unsigned char r, g, b,a; Byte r, g, b; int count; }; (NSInteger) processImage1: (UIImage*) image { // Allocate a buffer big enough to hold all the pixels struct pixel* pixels = (struct pixel*) calloc(1, image.size.width * image.size.height * sizeof(struct pixel)); if (pixels != nil) { // Create a new bitmap CGContextRef context = CGBitmapContextCreate( (void*) pixels, image.size.width, image.size.height, 8, image.size.width * 4, CGImageGetColorSpace(image.CGImage), kCGImageAlphaPremultipliedLast ); NSLog(@"1=%d, 2=%d, 3=%d", CGImageGetBitsPerComponent(image), CGImageGetBitsPerPixel(image),CGImageGetBytesPerRow(image)); if (context != NULL) { // Draw the image in the bitmap CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, image.size.width, image.size.height), image.CGImage); NSUInteger numberOfPixels = image.size.width * image.size.height; I confusing about how to initialize the 2-D matrix in which the matrix store data of pixels.

    Read the article

  • Byte order (endian) of int in NSLog?

    - by Eonil
    NSLog function accepts printf format specifiers. My question is about %x specifier. Does this print hex codes as sequence on memory? Or does it have it's own printing sequence style? unsigned int a = 0x000000FF; NSLog(@"%x", a); Results of above code on little or big endian processors are equal or different? And how about NSString's -initWithFormat method? Does it follows this rule equally?

    Read the article

  • `.' cannot appear in a constant-expression

    - by Amir Rachum
    Hi all, I'm getting the following error: `.' cannot appear in a constant-expression for this function (line 4): bool Covers(const Region<C,V,D>& other) const { const Region& me = *this; for (unsigned d = 0; d < D; d++) { if (me[d].min > other[d].min || me[d].max < other[d].max) { return false; } } can anyone explain the problem please?

    Read the article

  • Why am I not getting correct result when I calculate exponent with ^ in C++?

    - by xbonez
    I am using Bode's formuala to calculate distance of nth planet from sun dist = (4 + 3*(2^(n-2)))/10 If I calculate the distance this way, I get the right values: dist[2] = ((4 + 3*1)/10.0) ; dist[3] = ((4 + 3*2)/10.0) ; dist[4] = ((4 + 3*4)/10.0) ; But doing it this way, gives me incorrect values: vector <double> dist(5); for (unsigned int i = 2; i < 5; i++) { dist[i] = ((4 + 3*(2^(3-2)))/10.0) ; } Why so?

    Read the article

  • How to make a C program that can run x86 hex codes

    - by Iowa15
    I have an array of hex codes that translate into assembly instructions and I want to create program in C that can execute these. unsigned char rawData[5356] = { 0x4C, 0x01, 0x0A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x64, 0x0C, 0x00, 0x00, 0x3D, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x01, 0x2E, 0x74, 0x65, 0x78, 0x74, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xB4, 0x05, 0x00, 0x00, 0xA4, 0x01, 0x00, 0x00, 0x68, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x61, 0x00, 0x00, 0x00, 0x20, 0x00, 0x30, 0x60, 0x2E, 0x64, 0x61, 0x74, 0x61, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x30, 0xC0, 0x2E, 0x62, 0x73, 0x73, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x00, 0x30, 0xC0, 0x2F, 0x34, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x58, 0x07, 0x00, 0x00, 0x32, 0x0C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x20, 0x10, 0x30, 0x60, 0x2F, 0x33, 0x32, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x14, 0x00, 0x00, 0x00, 0x6C, 0x07, 0x00, 0x00,...and so on

    Read the article

  • Printing factorial at compile time in C++

    - by user519882
    template<unsigned int n> struct Factorial { enum { value = n * Factorial<n-1>::value}; }; template<> struct Factorial<0> { enum {value = 1}; }; int main() { std::cout << Factorial<5>::value; std::cout << Factorial<10>::value; } above program computes factorial value during compile time. I want to print factorial value at compile time rather than at runtime using cout. How can we achive printing the factorial value at compile time? I am using VS2009. Thanks!

    Read the article

  • What is the explanation for "warning: assuming that the loop is not infinite"

    - by James Morris
    I had just taken the decision to change as many variables from unsigned to int and upon recompiling the code in question, was greeted by this warning message: freespace_state.c:203: warning: assuming that the loop is not infinite The line in question: for (x = startx; x <= endx; ++x, ++xptr) This loop is 60 lines of code (inc white space/brackets etc), and has a goto within it, and at least one occurrence of continue. In this case, I think I am appreciative that GCC is assuming this loop is not infinite, because, it should never loop indefinitely. What is GCC trying to tell me here?

    Read the article

  • Possible compiler bug in MSVC12 (VS2013) with designated initializer

    - by diapir
    Using VS2013 Update 2, I've stumbled on some strange error message : // test.c int main(void) { struct foo { int i; float f; }; struct bar { unsigned u; struct foo foo; double d; }; struct foo some_foo = { .i = 1, .f = 2.0 }; struct bar some_bar = { .u = 3, // error C2440 : 'initializing' : cannot convert from 'foo' to 'int' .foo = some_foo, .d = 4.0 }; // Works fine some_bar.foo = some_foo; return 0; } Both GCC and Clang accept it. Am I missing something or does this piece of code exposes a compiler bug ? EDIT : Duplicate: Initializing struct within another struct using designated initializer causes compile error in Visual Studio 2013

    Read the article

  • How to make this jpeg compression faster

    - by Richard Knop
    I am using OpenCV to compress binary images from a camera: vector<int> p; p.push_back(CV_IMWRITE_JPEG_QUALITY); p.push_back(75); // JPG quality vector<unsigned char> jpegBuf; cv::imencode(".jpg", fIplImageHeader, jpegBuf, p); The code above compresses a binary RGB image stored in fIplImageHeader to a JPEG image. For a 640*480 image it takes about 0.25 seconds to execute the five lines above. Is there any way I could make it faster? I really need to repeat the compression more than 4 times a second.

    Read the article

  • JavaScript pack("d") - binary strings

    - by Tim Whitlock
    I'm trying to replicate the Perl and PHP style pack and unpack functions in JavaScript. Unsigned integers were easy enough, so my pack('n') and pack('N') are ok. But my lack of a computer science background is a hurdle now and I don't know where to start with pack('d') for packing JavaScript's standard floating point. Is there a JavaScript library for this out there? If not, is there a good resource where I can learn how to do this? I am fine with bitwise and binary level operations in JS, I just don't know where to start with the logic. Thanks.

    Read the article

  • Declaring a data type dynamically in C++

    - by Bobby
    I want to be able to do the following: I have an array of strings that contain data types: string DataTypeValues[20] = {"char", "unsigned char", "short", "int"}; Then later, I would like to create a variable of one of the data types at runtime. I won't know at compile time what the correct data type should be. So for example, if at runtime I determined a variable x needed to be of type int: DataTypeValues[3] x = 100; Obviously this won't work, so how could I do something like this?

    Read the article

  • How to prevent application thievery?

    - by Berdon Magnus
    Hey, I was wondering what the most effective way of preventing people from stealing my application (downloading a copy of the .apk online rather than buying it). I've spent a lot of time on one in particular (Droidbox) and won't be releasing Sync until I can guarantee that the people who are providing illegal copies of the pro version aren't able to. Anyone implemented this? I've tried checking my package signature verses an the signature of an unsigned copy but it appears to be the same - perhaps I'm doing something incorrectly here. I'm unsure whether people actually distribute the signed .apk in which case I don't think signature validation would work to begin with...

    Read the article

  • Is it a good idea to apply some basic macros to simplify code in a large project?

    - by DoctorT
    I've been working on a foundational c++ library for some time now, and there are a variety of ideas I've had that could really simplify the code writing and managing process. One of these is the concept of introducing some macros to help simplify statements that appear very often, but are a bit more complicated than should be necessary. For example, I've come up with this basic macro to simplify the most common type of for loop: #define loop(v,n) for(unsigned long v=0; v<n; ++v) This would enable you to replace those clunky for loops you see so much of: for (int i = 0, i < max_things; i++) With something much easier to write, and even slightly more efficient: loop (i, max_things) Is it a good idea to use conventions like this? Are there any problems you might run into with different types of compilers? Would it just be too confusing for someone unfamiliar with the macro(s)?

    Read the article

  • Convert hex to decimal keeping fractional part in Lua

    - by Zack Mulgrew
    Lua's tonumber function is nice but can only convert unsigned integers unless they are base 10. I have a situation where I have numbers like 01.4C that I would like to convert to decimal. I have a crummy solution: function split(str, pat) local t = {} local fpat = "(.-)" .. pat local last_end = 1 local s, e, cap = str:find(fpat, 1) while s do if s ~= 1 or cap ~= "" then table.insert(t,cap) end last_end = e+1 s, e, cap = str:find(fpat, last_end) end if last_end <= #str then cap = str:sub(last_end) table.insert(t, cap) end return t end -- taken from http://lua-users.org/wiki/SplitJoin function hex2dec(hexnum) local parts = split(hexnum, "[\.]") local sigpart = parts[1] local decpart = parts[2] sigpart = tonumber(sigpart, 16) decpart = tonumber(decpart, 16) / 256 return sigpart + decpart end print(hex2dec("01.4C")) -- output: 1.296875 I'd be interested in a better solution for this if there is one.

    Read the article

  • Three boolean values saved in one tinyint

    - by Casper
    Hello, probably a simple question but I seem to be suffering from programmer's block. :) I have three boolean values: A, B, and C. I would like to save the state combination as an unsigned tinyint (max 255) into a database and be able to derive the states from the saved integer. Even though there are only a limited number of combinations, I would like to avoid hard-coding each state combination to a specific value (something like if A=true and B=true has the value 1). I tried to assign values to the variables so (A=1, B=2, C=3) and then adding, but I can't differentiate between A and B being true from i.e. only C being true. I am stumped but pretty sure that it is possible. Thanks

    Read the article

< Previous Page | 148 149 150 151 152 153 154 155 156 157 158 159  | Next Page >