unsigned

Unsigned short in Java

由 六月ゝ 毕业季﹏ 提交于 2019-11-26 12:26:36
问题 How can I declare an unsigned short value in Java? 回答1: You can't, really. Java doesn't have any unsigned data types, except char . Admittedly you could use char - it's a 16-bit unsigned type - but that would be horrible in my view, as char is clearly meant to be for text: when code uses char , I expect it to be using it for UTF-16 code units representing text that's interesting to the program, not arbitrary unsigned 16-bit integers with no relationship to text. 回答2: If you really need a

Why is −1 > sizeof(int)?

由 匆匆过客 提交于 2019-11-26 11:37:33
问题 Consider the following code: template<bool> class StaticAssert; template<> class StaticAssert<true> {}; StaticAssert< (-1 < sizeof(int)) > xyz1; // Compile error StaticAssert< (-1 > sizeof(int)) > xyz2; // OK Why is -1 > sizeof(int) true? Is it true that -1 is promoted to unsigned(-1) and then unsigned(-1) > sizeof(int) . Is it true that -1 > sizeof(int) is equivalent to -1 > size_t(4) if sizeof(int) is 4. If this is so why -1 > size_t(4) is false? Is this C++ standard comformant? 回答1: The

MYSQL数据库类型与JAVA类型对应表

由 旧巷老猫 提交于 2019-11-26 10:58:23
MYSQL数据库类型与JAVA类型对应表 类型名称 显示长度 数据库类型 JAVA类型 JDBC类型 索引(int) VARCHAR L+N VARCHAR java.lang.String 12 CHAR N CHAR java.lang.String 1 BLOB L+N BLOB java.lang.byte[] -4 TEXT 65535 VARCHAR java.lang.String -1 INTEGER 4 INTEGER UNSIGNED java.lang.Long 4 TINYINT 3 TINYINT UNSIGNED java.lang.Integer -6 SMALLINT 5 SMALLINT UNSIGNED java.lang.Integer 5 MEDIUMINT 8 MEDIUMINT UNSIGNED java.lang.Integer 4 BIT 1 BIT java.lang.Boolean -7 BIGINT 20 BIGINT UNSIGNED java.math.BigInteger -5 FLOAT 4+8 FLOAT java.lang.Float 7 DOUBLE 22 DOUBLE java.lang.Double 8 DECIMAL 11 DECIMAL java.math.BigDecimal 3 BOOLEAN 1

what is the unsigned datatype?

由 独自空忆成欢 提交于 2019-11-26 10:33:40
问题 I\'ve seen this unsigned \"typeless\" type used a couple of times, but never seen an explanation for it. I suppose there\'s a corresponding signed type. Here\'s an example: static unsigned long next = 1; /* RAND_MAX assumed to be 32767 */ int myrand(void) { next = next * 1103515245 + 12345; return(( unsigned )(next/65536) % 32768); } void mysrand( unsigned seed ) { next = seed; } What I have gathered so far: - on my system, sizeof(unsigned) = 4 (hints at a 32-bit unsigned int) - it might be

Qt开源编辑器qsciscintilla的使用笔记

由 雨燕双飞 提交于 2019-11-26 10:14:50
首先放一张做的软件中的编辑器的效果图 中间红色的框就是放在Qt的tabwidget控件中的qsciscintilla编辑器 先从官网下载qsciscintilla源码，在qtcreater中编译，提取静态库和头文件，将库和Qsci中的头文件添加到自己的项目的pro配置文件中，具体编译方法可参考网上的帖子，这类帖子比较多这里不再赘述，可以运行之后再看下面的操作 1，一些常规设置，都是通过对应的函数来设置 //设置字体QFont font("Courier", 10, QFont::Normal); ui->textEdit->setFont(font); ui->textEdit->setMarginsFont(font); QFontMetrics fontmetrics = QFontMetrics(font);//设置左侧行号栏宽度等 ui->textEdit->setMarginWidth(0, fontmetrics.width("00000")); ui->textEdit->setMarginLineNumbers(0, true); ui->textEdit->setBraceMatching(QsciScintilla::SloppyBraceMatch); ui->textEdit->setTabWidth(4);//设置括号等自动补全 ui->textEdit-

Unsigned hexadecimal constant in C?

由 时光总嘲笑我的痴心妄想 提交于 2019-11-26 09:39:53
问题 Does C treat hexadecimal constants (e.g. 0x23FE) and signed or unsigned int? 回答1: The number itself is always interpreted as a non-negative number. Hexadecimal constants don't have a sign or any inherent way to express a negative number. The type of the constant is the first one of these which can represent their value: int unsigned int long int unsigned long int long long int unsigned long long int 回答2: It treats them as int literals(basically, as signed int!). To write an unsigned literal

Signed versus Unsigned Integers

由 ぐ巨炮叔叔 提交于 2019-11-26 09:10:44
Am I correct to say the difference between a signed and unsigned integer is: Unsigned can hold a larger positive value, and no negative value. Unsigned uses the leading bit as a part of the value, while the signed version uses the left-most-bit to identify if the number is positive or negative. signed integers can hold both positive and negative numbers. Any other differences? Greg Unsigned can hold a larger positive value, and no negative value. Yes. Unsigned uses the leading bit as a part of the value, while the signed version uses the left-most-bit to identify if the number is positive or

performance of unsigned vs signed integers

由 荒凉一梦 提交于 2019-11-26 08:55:52
问题 Is there any performance gain/loss by using unsigned integers over signed integers? If so, does this goes for short and long as well? 回答1: Division by powers of 2 is faster with unsigned int , because it can be optimized into a single shift instruction. With signed int , it usually requires more machine instructions, because division rounds towards zero , but shifting to the right rounds down . Example: int foo(int x, unsigned y) { x /= 8; y /= 8; return x + y; } Here is the relevant x part

How to printf “unsigned long” in C?

由 柔情痞子 提交于 2019-11-26 08:40:04
问题 I can never understand how to print unsigned long datatype in C. Suppose unsigned_foo is an unsigned long , then I try: printf(\"%lu\\n\", unsigned_foo) printf(\"%du\\n\", unsigned_foo) printf(\"%ud\\n\", unsigned_foo) printf(\"%ll\\n\", unsigned_foo) printf(\"%ld\\n\", unsigned_foo) printf(\"%dl\\n\", unsigned_foo) And all of them print some kind of -123123123 number instead of unsigned long that I have. 回答1: %lu is the correct format for unsigned long . Sounds like there are other issues at

Difference between unsigned and unsigned int in C

由 无人久伴 提交于 2019-11-26 08:22:37
问题 Could you please make it clear what the difference is between unsigned and unsigned int ? Maybe some example code would be helpful. 回答1: unsigned is a modifier which can apply to any integral type ( char , short , int , long , etc.) but on its own it is identical to unsigned int . 回答2: There is no difference. unsigned and unsigned int are both synonyms for the same type (the unsigned version of the int type). 回答3: unsigned alone means unsigned int. You can also use unsigned char , etc. I have
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