将BOOL数组初始化为TRUE ??

编程入门行业动态更新时间:2024-10-19 19:38:09

本文介绍了将BOOL数组初始化为TRUE ??的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！问题描述

BOOL bMyarray [1000]; memset（bMyArray，0xFF，sizeof（BOOL）* 1000）; clean&快速直到别人的代码发现我返回-1到意味着真实因为我的BOOL是4个字节长，所以内存中的TRUE可以解决作为01 00 00 00这是一个正确的痛苦。在for循环中执行它是10倍慢btw。这是一个多余的问题，还有另外一种方法吗？ TIA

BOOL bMyarray[1000]; memset(bMyArray , 0xFF, sizeof(BOOL) * 1000); clean & quick until someone else''s code found I was returning -1 to mean true Because my BOOL is 4 bytes long, TRUE in memory works out as 01 00 00 00 which is a right pain. Doing it in a for loop is 10 x slower btw. Bit of a numpty question this, is there another way? TIA

推荐答案

Simon L写道： Simon L wrote: BOOL bMyarray [1000]; memset（bMyArray，0xFF，sizeof（BOOL）* 1000）; clean&快速直到别人的代码发现我返回-1到意味着真实因为我的BOOL是4个字节长，所以内存中的TRUE可以解决如01 00 00 00这是一个正确的痛苦。 BOOL bMyarray[1000]; memset(bMyArray , 0xFF, sizeof(BOOL) * 1000); clean & quick until someone else''s code found I was returning -1 to mean true Because my BOOL is 4 bytes long, TRUE in memory works out as 01 00 00 00 which is a right pain.

为什么不使用bool？ - Ian Collins。

Why not use bool? -- Ian Collins.

为什么不使用bool？ - 伊恩柯林斯。 Why not use bool? -- Ian Collins.

我在C工作（oops，错误组......）

I''m working in C (oops, wrong group..)

Simon L< si*******@hotmailwrites： Simon L <si*******@hotmailwrites: BOOL bMyarray [1000]; memset（bMyArray，0xFF，sizeof （BOOL）* 1000）; clean&快速直到别人的代码发现我返回-1到意味着真实因为我的BOOL是4个字节长，所以内存中的TRUE可以解决作为01 00 00 00这是一个正确的痛苦。在for循环中执行它是10倍慢btw。这是一个多余的问题，还有另外一种方法吗？ BOOL bMyarray[1000]; memset(bMyArray , 0xFF, sizeof(BOOL) * 1000); clean & quick until someone else''s code found I was returning -1 to mean true Because my BOOL is 4 bytes long, TRUE in memory works out as 01 00 00 00 which is a right pain. Doing it in a for loop is 10 x slower btw. Bit of a numpty question this, is there another way?

如果您有很多布尔值，可能值得将它们存储为位。使用更少的内存，更多的向量将保留在L1缓存中，因此访问它们的将更快（即使考虑到打包/解包）： #include< iostream> #include< limits.h> typedef int bit; //一位，0或1 typedef int word; //一些比特 #ifndef WORD_BIT #define WORD_BIT（sizeof（word）* CHAR_BIT） #endif class bit_vector { protected： unsigned int dimension; word * words; public： bit_vector（unsigned int dimension）{ this-> dimension = dimension; this-> words = new word [（this-> dimension + WORD_BIT-1）/ WORD_BIT]; } virtual~bit_vector（）{ delete [] this-> words; } 内联位运算符[]（unsigned int index）{ return（（index<） ; this-> dimension）？（1&（this-> words [index / WORD_BIT]>>（index％WORD_BIT）））： 0）; } 内联位设置（unsigned int index，bit value）{ if（index< this-> dimension）{ if（value == 0）{ this-> words [index / WORD_BIT]& =（〜（1<<（index％WORD_BIT）））; } else { this-> words [index / WORD_BIT] | =（1<<（index％WORD_BIT））; } $ return（value）; } //所以现在填充向量的速度将快256倍：无效填充（位值）{ word filler =（value == 0）？（0）:(〜0）; for（unsigned int i = 0; i<（this-> dimension + WORD_BIT-1））/ WORD_BIT; i ++）{this-> words [i] = filler;使用命名空间std; }; int main（void）{ bit_vector v（1000）; v.fill（1）; cout<< v [0]<<" ;，"<< v [999]<< endl; v.fill（0）; cout<<< v [0]< ;<"，"<< v [999]<< endl; v.set（0,1）; cout<< ; v [0]<<"，"<< v [999]<< endl; v.set（999,1）; cout<< v [0]<<"，"<< v [999]<< endl; return（0）; } - __Pascal Bourguignon__

If you have a lot of booleans, it may be worthwhile to store them as bits. Using less memory, more of the vector will stay in L1-cache, so accessing them will be faster (even considering the bit packing/unpacking): #include <iostream> #include <limits.h> typedef int bit; // one bit, 0 or 1 typedef int word; // some bits #ifndef WORD_BIT #define WORD_BIT (sizeof(word)*CHAR_BIT) #endif class bit_vector { protected: unsigned int dimension; word* words; public: bit_vector(unsigned int dimension){ this->dimension=dimension; this->words=new word[(this->dimension+WORD_BIT-1)/WORD_BIT]; } virtual ~bit_vector(){ delete [] this->words; } inline bit operator[](unsigned int index){ return((index<this->dimension) ?(1&(this->words[index/WORD_BIT]>>(index%WORD_BIT))) :0); } inline bit set(unsigned int index,bit value){ if(index<this->dimension){ if(value==0){ this->words[index/WORD_BIT]&=(~(1<<(index%WORD_BIT))); }else{ this->words[index/WORD_BIT]|=(1<<(index%WORD_BIT)); }} return(value); } // so now filling the vector will be 256 times faster: void fill(bit value){ word filler=(value==0)?(0):(~0); for(unsigned int i=0;i<(this->dimension+WORD_BIT-1)/WORD_BIT;i++){ this->words[i]=filler; }} }; using namespace std; int main(void){ bit_vector v(1000); v.fill(1); cout<<v[0]<<", "<<v[999]<<endl; v.fill(0); cout<<v[0]<<", "<<v[999]<<endl; v.set(0,1); cout<<v[0]<<", "<<v[999]<<endl; v.set(999,1); cout<<v[0]<<", "<<v[999]<<endl; return(0); } -- __Pascal Bourguignon__