unsigned

问题 In C/C++, is there a difference between saying (1U) vs. ((unsigned int)1) ? I prefer the second one, but I am concerned that the second one may be type-cast at run time (i.e. extra cpu cycles), whereas the first one gets the correct type at compilation. Thanks. 回答1: They're not equivalent. 1U is valid in #if preprocessing directives. (unsigned int)1 is a syntax error at the preprocessor level. You could however make it (unsigned)+1 and it would be valid in the preprocessor, but only because

问题 I am creating a Java Persistence Entity Bean (with NetBeans IDE 8.0.1) based on an existing table in a MySQL database. I've come across a field in this table which is of type "Unsigned TINYINT(3)" . I have found that the following can be done to define the type of a column as an unsigned int: private long foo; @Column(columnDefinition = "UNSIGNED INT(11)") public long getFoo() { return foo; } Steps to reproduce the problem: I am trying to create a field as follows: @Size(max = 3) @Column(name

问题 this must be simple, but i'm missing it. i have a complex model that has >32767 vertices. now, the indices can only be passed to opengl as type GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT. java has no concept of unsigned, so the unsigned short option maps to simply (signed) short, which is 16 bits, or +32767. when i specify the vertices, i need to pass opengl a short[], where the values in the array point to a vertex in the vertice array. however, if there are >32767 vertices, the value won't fit

问题 This question already has answers here : What happens if I assign a negative value to an unsigned variable? (5 answers) Closed last year . In this answer, you can find this comment: Strictly speaking the bit representations of the two numbers before conversion being the same doesn't matter. Even with 1's complement or signed magnitude representations, the conversion of (signed) -1 to unsigned long will always result in ULONG_MAX . (The bit pattern will be the same after conversion of course).

问题 I have made an unsigned .IPA app using xcode 6 and swift language. I have compressed the .app file and change its extention to .ipa. When I want to install this .ipa file on my jailbreaked iPhone, this error is appeard: "the app 'youtapp.ipa' could not be added to your iTunes library because it is not a valid app". Would you please let me know what the problem is. 回答1: In my case I was using the "Save for Ad Hoc Deployment" option from Organizer to create an ipa file. It appears however that

问题 The size of an unsigned int in C is 0 to 65,535 or 0 to 4,294,967,295 . I tested with the following codes in C: unsigned int number = 0; number -= 300; printf("%d\n", number); OUTPUT: -300 I remember that if the value of unsigned int variable goes below 0, it should wrap around and I was expecting the output to be something like 4294966996 . However the output printed from the console is -300 . I tested similar statements in C++, it does give me 4294966996 . My question is: Why is the output

问题 I need to convert unicode strings in Python to other types such as unsigned and signed int 8 bits,unsigned and signed int 16 bits,unsigned and signed int 32 bits,unsigned and signed int 64 bits,double,float,string,unsigned and signed 8 bit,unsigned and signed 16 bit, unsigned and signed 32 bit,unsigned and signed 64 bit. I need help from u people. 回答1: use int() to convert the string to an integer. Python doesn't have different fixed-width integers so you'll just get one type of thing out.

问题 Recently, during a refactoring session, I was looking over some code I wrote and noticed several things: I had functions that used unsigned char to enforce values in the interval [0-255]. Other functions used int or long data types with if statements inside the functions to silently clamp the values to valid ranges. Values contained in classes and/or declared as arguments to functions that had an unknown upper bound but a known and definite non-negative lower bound were declared as an

问题 I just saw some C++ code like this. It was using a condition to decide whether to walk forward or backward through a std::vector . The compiler doesn't complain, but I thought size_t was unsigned. Is this dangerous? vector<int> v { 1,2,3,4,5 }; bool rev = true; size_t start, end, di; if (rev) { start = v.size()-1; end = -1; di = -1; } else { start = 0; end = v.size(); di = 1; } for (auto i=start; i!=end; i+=di) { cout << v[i] << endl; } 回答1: It's well defined to use unsigned integers (and

问题 now the newer error "narrowing conversion of long long int to long unsigned int inside {} [-Wnarrowing]" the source code relative to it: // Implements the joint conditional cummulative density functions for CP-nets // For node j in the lexicographic topological sort as defined by the dag code: // the table gives P( s, t | n, c, j ). // The number of rows in each table is the triangular number of min(c, j). #ifndef TABLES_H #define TABLES_H #include <random> // Mersenne Twister #include