代码有注释
双斜线冒号开始的一行表示源文件的第1行
原文件的最后一行包括3条斜线，其后是一个冒号和一个波形号
//: C03:ExtractCode.cpp {-edg} {RunByHand}
// From "Thinking in C++, Volume 2", by Bruce Eckel & Chuck Allison.
// (c) 1995-2004 MindView, Inc. All Rights Reserved.
// See source code use permissions stated in the file 'License.txt',
// distributed with the code package available at www.MindView.net.
// Extracts code from text.
#include <cassert>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <fstream>
#include <iostream>
#include <string>
using namespace std;
// Legacy non-standard C header for mkdir()
#if defined(__GNUC__) || defined(__MWERKS__)
#include <sys/stat.h>
#elif defined(__BORLANDC__) || defined(_MSC_VER) \
|| defined(__DMC__)
#include <direct.h>
#else
#error Compiler not supported
#endif
// Check to see if directory exists
// by attempting to open a new file
// for output within it.
bool exists(string fname) {
size_t len = fname.length();
if(fname[len-1] != '/' && fname[len-1] != '\\')
fname.append("/");
fname.append("000.tmp");
ofstream outf(fname.c_str());
bool existFlag = outf;
if(outf) {
outf.close();
remove(fname.c_str());
}
return existFlag;
}
int main(int argc, char* argv[]) {
// See if input file name provided
if(argc == 1) {
cerr << "usage: extractCode file [dir]" << endl;
exit(EXIT_FAILURE);
}
// See if input file exists
ifstream inf(argv[1]);
if(!inf) {
cerr << "error opening file: " << argv[1] << endl;
exit(EXIT_FAILURE);
}
// Check for optional output directory
string root("./"); // current is default
if(argc == 3) {
// See if output directory exists
root = argv[2];
if(!exists(root)) {
cerr << "no such directory: " << root << endl;
exit(EXIT_FAILURE);
}
size_t rootLen = root.length();
if(root[rootLen-1] != '/' && root[rootLen-1] != '\\')
root.append("/");
}
// Read input file line by line
// checking for code delimiters
string line;
bool inCode = false;
bool printDelims = true;
ofstream outf;
while(getline(inf, line)) {
size_t findDelim = line.find("//" "/:~");
if(findDelim != string::npos) {
// Output last line and close file
if(!inCode) {
cerr << "Lines out of order" << endl;
exit(EXIT_FAILURE);
}
assert(outf);
if(printDelims)
outf << line << endl;
outf.close();
inCode = false;
printDelims = true;
} else {
findDelim = line.find("//" ":");
if(findDelim == 0) {
// Check for '!' directive
if(line[3] == '!') {
printDelims = false;
++findDelim; // To skip '!' for next search
}
// Extract subdirectory name, if any
size_t startOfSubdir =
line.find_first_not_of(" \t", findDelim+3);
findDelim = line.find(':', startOfSubdir);
if(findDelim == string::npos) {
cerr << "missing filename information\n" << endl;
exit(EXIT_FAILURE);
}
string subdir;
if(findDelim > startOfSubdir)
subdir = line.substr(startOfSubdir,
findDelim - startOfSubdir);
// Extract file name (better be one!)
size_t startOfFile = findDelim + 1;
size_t endOfFile =
line.find_first_of(" \t", startOfFile);
if(endOfFile == startOfFile) {
cerr << "missing filename" << endl;
exit(EXIT_FAILURE);
}
// We have all the pieces; build fullPath name
string fullPath(root);
if(subdir.length() > 0)
fullPath.append(subdir).append("/");
assert(fullPath[fullPath.length()-1] == '/');
if(!exists(fullPath))
#if defined(__GNUC__) || defined(__MWERKS__)
mkdir(fullPath.c_str(), 0); // Create subdir
#else
mkdir(fullPath.c_str()); // Create subdir
#endif
fullPath.append(line.substr(startOfFile,
endOfFile - startOfFile));
outf.open(fullPath.c_str());
if(!outf) {
cerr << "error opening " << fullPath
<< " for output" << endl;
exit(EXIT_FAILURE);
}
inCode = true;
cout << "Processing " << fullPath << endl;
if(printDelims)
outf << line << endl;
}
else if(inCode) {
assert(outf);
outf << line << endl; // Output middle code line
}
}
}
exit(EXIT_SUCCESS);
} ///:~输出
运行前要带个参数 弄到一个cpp文件 Tracetst.cpp
//: C03:Tracetst.cpp {-bor}
// From "Thinking in C++, Volume 2", by Bruce Eckel & Chuck Allison.
// (c) 1995-2004 MindView, Inc. All Rights Reserved.
// See source code use permissions stated in the file 'License.txt',
// distributed with the code package available at www.MindView.net.
#include <iostream>
#include <fstream>
#include "../require.h"
using namespace std;
#define TRACEON
#include "Trace.h"
int main() {
ifstream f("Tracetst.cpp");
assure(f, "Tracetst.cpp");
cout << f.rdbuf(); // Dumps file contents to file
getchar();
} ///:~
运行过后 会在程序当前目录创建一个文件夹C03
C03里面生成 Tracetst.cpp
跟原先的Tracetst.cpp内容一样
在文件系统中创建目录的mkdir()函数，是由POSIX标准在头文件
<sys/stat.h>中定义的
遗憾的是，很多编译器仍在使用不同的另一个头文件 direct.h
ExtraceCode.cpp 中的exists()函数通过打开目录中一个临时文件的
方式来判断这个目录存在。如果打开文件失败，目录就不存在。
要输出一个文件，可以将char*型名字传送到std::remove