【发布时间】：2009-10-11 18:14:07
【问题描述】：
我有以下代码，到目前为止，我想检查一个文件名是否已经在链表fileList（或flist）中。根据输出，保存在第一个节点中的字符串在Node* getFileName(Node *&flist) 某处发生了更改这是怎么发生的？另外，关于节点和字符串的指针，我做的还有什么是错误的或不安全的吗？
输出：
在主要：file4.txt 进程开始：file4.txt 文件4.txt 进程中间：file4.txt" 包含，节点中的文件名：file4.txt" 在包含，目标文件名：file4.txt 进程结束：file4.txt" 0 没有递归调用代码：
struct Node {
string fileName;
Node *link;
};
/*
*
*/
bool contains (Node *&flist, string &name) {
Node *tempNode = *&flist;
while (tempNode != 0) {
cout << "in contains, fileName in node: " << flist->fileName << endl;
cout << "in contains, target file name: " << name << endl;
if ((tempNode->fileName) == name) {
return true;
}
else {
tempNode = tempNode->link;
}
}
return false;
}
/*
*
*/
Node* getLastNode (Node *&flist) {
Node *tempNode = *&flist;
while (tempNode != 0) {
tempNode = tempNode->link;
}
return tempNode;
}
/*
*
*/
string getFileName(string oneLine) {
char doubleQuote;
doubleQuote = oneLine[9];
if (doubleQuote == '\"') {
string sub = oneLine.substr(10); //getting the file name
string::size_type n = sub.size();
sub = sub.substr(0,n-1);
cout << sub << endl;
return sub;
}
return NULL;
}
/*
*
*/
void process( istream &in, ostream &out, Node *&flist ) {
cout << "start of process: " << flist->fileName << endl;
string oneLine; //temp line holder
while (getline(in, oneLine)) {
// cout << oneLine << endl;
string::size_type loc = oneLine.find("#include",0);
if (loc != string::npos) {
//found one line starting with "#include"
string name;
name = getFileName(oneLine);
cout << "mid of process: " << flist->fileName << endl;
bool recursive;
recursive = contains(flist, name);
cout << "end of process: " << flist->fileName << endl;
cout << recursive << endl;
if (recursive) {
//contains recursive include
cerr << "recursive include of file " << name << endl;
exit(-1);
}
else {
//valid include
cout << "no recursive call" << endl;
}//else
}//if
}//while
}//process
/*
*
*/
int main( int argc, char *argv[] ) {
istream *infile = &cin; // default value
ostream *outfile = &cout; // default value
Node* fileList;
switch ( argc ) {
case 3:
outfile = new ofstream( argv[2] ); // open the outfile file
if ( outfile->fail() ) {
cerr << "Can't open output file " << argv[2] << endl;
exit( -1 );
}
// FALL THROUGH to handle input file
case 2:
infile = new ifstream( argv[1] ); // open the input file
if ( infile->fail() ) {
cerr << "Can't open input file " << argv[1] << endl;
exit( -1 );
}
else {
Node aFile = {argv[1], 0};
fileList = &aFile;
cout << "in main: " << fileList->fileName << endl;
}
// FALL THROUGH
case 1: // use cin and cout
break;
default: // too many arguments
cerr << "Usage: " << argv[0] << " [ input-file [ output-file ] ]" << endl;
exit( -1 ); // TERMINATE!
}
processOneFile (*infile, *outfile, fileList);
// do something
if ( infile != &cin ) delete infile; // close file, do not delete cin!
if ( outfile != &cout ) delete outfile; // close file, do not delete cout!
}
【问题讨论】：
-
您是否尝试过使用调试器单步执行您的代码？它应该比使用
print语句来显示哪个语句更改了您的数据更成功。 -
能否请您提供编译此文件所需的文件？
-
我还建议使用 std::set 来维护文件名而不是自制列表。
标签： c++ string pointers linked-list