c ++：在外部声明和填充地图

Question

所以我一直在尝试整理我的代码，并且想知道是否有办法声明我的地图并将它们填充到其他文件甚至其他函数中。

到目前为止，这是我的代码：（这使用了一个我没有代码的内置标记器，但基本上地图存储输入机器代码的二进制文件，并将输出 a 指令和 c 指令，具体取决于输入）

代码：

// 将 Hack 程序集转换为二进制

#include <iostream>
#include "tokens.h"
#include <bitset>
#include <cctype>
#include <string>
#include <map>

using namespace std ;

bool isNumber(string s){
    for (size_t n = 0; n < s.length(); n++){
        if (!(isdigit(s[n]))){
            return false;
        } else {
            return true;
        }
    }    
}

int main(){
// Declaring lookup tables (want to make this global [seperate file])
std::map<std::string, std::string> compTable;
std::map<std::string, std::string> destTable;
std::map<std::string, std::string> jumpTable;

// Inserting table data (want to make this global [seperate file])
// Jump Table Data
    jumpTable.insert(pair<string, string> ("NULL", "000"));
    jumpTable.insert(pair<string, string> ("JGT", "001"));
    jumpTable.insert(pair<string, string> ("JEQ", "010"));
    jumpTable.insert(pair<string, string> ("JGE", "011"));
    jumpTable.insert(pair<string, string> ("JLT", "100"));
    jumpTable.insert(pair<string, string> ("JNE", "101"));
    jumpTable.insert(pair<string, string> ("JLE", "110"));
    jumpTable.insert(pair<string, string> ("JMP", "111"));

// Dest Table Data
    destTable.insert(pair<string, string> ("NULL", "000"));
    destTable.insert(pair<string, string> ("M", "001"));
    destTable.insert(pair<string, string> ("D", "010"));
    destTable.insert(pair<string, string> ("MD", "011"));
    destTable.insert(pair<string, string> ("A", "100"));
    destTable.insert(pair<string, string> ("AM", "101"));
    destTable.insert(pair<string, string> ("AD", "110"));
    destTable.insert(pair<string, string> ("AMD", "111"));

// Comp Table Data
    // When a=1
    compTable.insert(pair<string, string> ("0", "1110101010"));
    compTable.insert(pair<string, string> ("1", "1110111111"));
    compTable.insert(pair<string, string> ("-1", "1110111010"));
    compTable.insert(pair<string, string> ("D", "1110001100"));
    compTable.insert(pair<string, string> ("A", "1110110000"));
    compTable.insert(pair<string, string> ("!D", "1110001101"));
    compTable.insert(pair<string, string> ("!A", "1110110001"));
    compTable.insert(pair<string, string> ("-D", "1110001111"));
    compTable.insert(pair<string, string> ("-A", "1110110011"));
    compTable.insert(pair<string, string> ("D+1", "1110011111"));
    compTable.insert(pair<string, string> ("A+1", "1110110111"));
    compTable.insert(pair<string, string> ("D-1", "1110001110"));
    compTable.insert(pair<string, string> ("A-1", "1110110010"));
    compTable.insert(pair<string, string> ("D+A", "1110000010"));
    compTable.insert(pair<string, string> ("D-A", "1110010011"));
    compTable.insert(pair<string, string> ("A-D", "1110000111"));
    compTable.insert(pair<string, string> ("D&A", "1110000000"));
    compTable.insert(pair<string, string> ("D|A", "1110010101"));
    // when a=0
    compTable.insert(pair<string, string> ("M", "1111110000"));
    compTable.insert(pair<string, string> ("!M", "1111110001"));
    compTable.insert(pair<string, string> ("-M", "1111110011"));
    compTable.insert(pair<string, string> ("M+1", "1111110111"));
    compTable.insert(pair<string, string> ("M-1", "1111110010"));
    compTable.insert(pair<string, string> ("D+M", "1111000010"));
    compTable.insert(pair<string, string> ("D-M", "1111010011"));
    compTable.insert(pair<string, string> ("M-D", "1111000111"));
    compTable.insert(pair<string, string> ("D&M", "1111000000"));
    compTable.insert(pair<string, string> ("D|M", "1111010101"));

// Declaring Variables
    string temp;
    string tempValue;
    int skipLine = 0;
    int tokenCounter = 0;

// create a new assembler tokeniser then read the first token
tokens *tokeniser = new tokens(getchar) ;
std::string token = tokeniser->next_token() ;

while ( token != "?" )          // stop at EOF, "?" denotes EOF
{
    if(tokenCounter > 0) {
        cout << endl;
    }
    if(skipLine == 1) {
        cout << endl;
    }
    skipLine = 0;
    if(token == "address"){
        string adrsStr = tokeniser->token_value();
        if(isNumber(adrsStr)==true){
            int adrs = stoi(adrsStr);
            cout << bitset<16>(adrs);
        }
    }
    if(token == "comp" || token == "dest" || token == "dest-comp?" || token == "null"){
        tempValue = tokeniser->token_value();
        temp = token;
        token = tokeniser->next_token() ;
        if(token == "equals"){
            token = tokeniser->next_token() ;
            if(temp == "null") {
                    std::cout << compTable.find(tokeniser->token_value())->second;
                    std::cout << destTable.find("NULL")->second;
                    std::cout << jumpTable.find("NULL")->second;
            }else if(temp == "dest" || temp == "dest-comp?"){
                if (token == "comp" || token == "dest-comp?"){
                    std::cout << compTable.find(tokeniser->token_value())->second;
                    std::cout << destTable.find(tempValue)->second;
                    std::cout << jumpTable.find("NULL")->second;
                }
            }
        }else if(token == "semi") {
            std::cout << compTable.find(tempValue)->second;
            std::cout << destTable.find("NULL")->second;    
            token = tokeniser->next_token() ;
            if (token == "jump"){
                std::cout << jumpTable.find(tokeniser->token_value())->second;
            } else if(token == "null") {
                std::cout <<jumpTable.find("NULL")->second;
            }
        }else if (token != "equal" || token != "semi"){
            std::cout << compTable.find(tempValue)->second;
            std::cout << destTable.find("NULL")->second;  
            std::cout << jumpTable.find("NULL")->second;
            if (token!= "semi" || token!="equals"){
                skipLine=1;
                continue;
            }
        }
    }
    tokenCounter++;
    token = tokeniser->next_token() ;


}
cout << endl;
/*cout << jumpTable.find("NULL")->second << endl;
cout << compTable.find("A")->second << endl;
cout << destTable.find("A")->second << endl;*/
return 0 ;
}

地图的首选格式将包含一个用于在外部声明地图的 create() 函数和一个用于填充地图的 insert() 函数

这可能吗？

Answer 1

你可以这样做：

std::map<std::string, std::string> make_jump_table()
{
    return {
        {"NULL", "000"},
        {"JGT", "001"},
        {"JEQ", "010"},
        {"JGE", "011"},
        {"JLT", "100"},
        {"JNE", "101"},
        {"JLE", "110"},
        {"JMP", "111"}
    };
}

Answer 2

用老式的方式来做怎么样？通过使用extern 并提供一个main() 应该调用的函数来执行所有插入操作。

我基于this 编写了一个示例，您可以根据该示例编写代码（我无法这样做，因为我没有您的令牌标头）。

main.cpp

#include <iostream>
#include <map>
#include "myMap.h"

std::map<char,int> mymap;

int main ()
{
  myMapInsertions(mymap);

  std::cout << "mymap contains:\n";
  for (std::map<char,int>::iterator it=mymap.begin(); it!=mymap.end(); ++it)
    std::cout << it->first << " => " << it->second << '\n';

  return 0;
}

我的地图.h

#ifndef MYMAP_H_
#define MYMAP_H_

#include <map>

extern std::map<char,int> mymap;

void myMapInsertions(std::map<char,int>& mymap);

#endif // MYMAP_H_

我的地图.cpp

#include "myMap.h"

void myMapInsertions(std::map<char,int>& mymap)
{
    mymap.insert ( std::pair<char,int>('a',100) );
    mymap.insert ( std::pair<char,int>('z',200) );
}

像这样编译：

g++ -Wall main.cpp myMap.cpp -o main

---

在此处了解 extern 关键字：When to use extern in C++?

Answer 3

在 C++11 中检查字符串是否为数字的另一种方法：

bool isNumber(const string& str) {
    int res = std::accumulate(str.begin(), str.end(), 0, [](int r, char c){return r += isdigit(c);});

    return (res == str.size());
}