我用我的.cpp代码得到的错误是我无法弄清楚的。我相信它可能是一个错过匹配的支架或什么的，但我不明白。这是代码和错误：
错误：
C:\Users\Tyler\Desktop\Program 2\p2.cpp:202: error: expected primary-expression before "else"
C:\Users\Tyler\Desktop\Program 2\p2.cpp:202: error: expected `;' before "else"
C:\Users\Tyler\Desktop\Program 2\p2.cpp:222: error: expected `while' before '(' token
C:\Users\Tyler\Desktop\Program 2\p2.cpp:223: error: expected `;' before '{' token
C:\Users\Tyler\Desktop\Program 2\p2.cpp:236: error: expected primary-expression before "else"
C:\Users\Tyler\Desktop\Program 2\p2.cpp:236: error: expected `;' before "else"
C:\Users\Tyler\Desktop\Program 2\p2.cpp: At global scope:
C:\Users\Tyler\Desktop\Program 2\p2.cpp:250: error: expected unqualified-id before "while"
C:\Users\Tyler\Desktop\Program 2\p2.cpp:250: error: expected `,' or `;' before "while"
C:\Users\Tyler\Desktop\Program 2\p2.cpp:251: error: expected unqualified-id before "return"
C:\Users\Tyler\Desktop\Program 2\p2.cpp:251: error: expected `,' or `;' before "return"
C:\Users\Tyler\Desktop\Program 2\p2.cpp:252: error: expected declaration before '}' token
代码：
int main()
{
Stack s; //variable declarations
StackItem *newItem;
char token, nextChar, prevChar, response, check;
int lineCount, apostCount;
char filename[50];
bool insideComment = false, insideString = false, error, isMatch, delimError = false;
fstream sourceFile;
do //do while response is y
{
do //do while opening the source file fails
{
cout << "Enter filename of source file: ";
cin.getline (filename,51);
sourceFile.open(filename); //opens the file with given filename
if (sourceFile.fail())
cout << "File could not be opened" << endl; //error if can't open
sourceFile.clear();
}
while (sourceFile.fail()); //exits if source file doesn't fail
sourceFile.clear();
lineCount = 0; //initializes line count to zero
while (!sourceFile.eof()) //exits if end of source file is reached
{
sourceFile.get(nextChar); //gets the next character in file
if (!sourceFile.eof()) //if not the end of source file
{
if ((int)nextChar == '\n') //if next character is an end line
{
lineCount++; //increments line count
cout << "Line count: " << lineCount << endl; //echoes line count
}
else if (nextChar == '{' || nextChar == '[' || nextChar == '(')
{ //continues if next char is an opening token
newItem->token = nextChar; //sets newItem's token
newItem->lineNumber = lineCount; //sets newItem's line count
if (!s.isFull()) //continues if stack isn't full
s.push(newItem); //pushes newItem onto the stack
s.displayStack(); //displays the stack
}
else if (nextChar == '}' || nextChar == ']' || nextChar == ')')
{ //continues if next char is a closing token
if (!s.isEmpty()) //continues if stack isn't empty
{
isMatch = s.matchStack(nextChar); //checks if token matches top
if (isMatch == true) //if true, pops the top of the stack
s.pop();
else //continues if match is false
{
newItem->token = nextChar; //sets newItem's token
newItem->lineNumber = lineCount; //sets newITem's line count
s.trailingItem(newItem); //calls the trailingItem function
cout << endl << endl << "Process another file? (y/n): ";
cin >> response; //asks user whether to continue
while (response != 'y' && response != 'n') //checks for input error
{
cout << "Error! Must enter either y for yes or n for no." << endl;
cout << endl << endl << "Process another file? (y/n): ";
cin >> response;
}
break; //leaves the while loop
}
}
else if (s.isEmpty()) //continues if stack is empty
{
newItem->token = nextChar; //sets newItem's token
newItem->lineNumber = lineCount; //sets newItem's line count
s.push(newItem); //pushes newItem onto the top of the stack
s.processStack(); //processes the error
cout << endl << endl << "Process another file? (y/n): ";
cin >> response; //asks user whether to continue
while (response != 'y' && response != 'n') //checks for input error
{
cout << "Error! Must enter either y for yes or n for no." << endl;
cout << endl << endl << "Process another file? (y/n): ";
cin >> response; //gets user input
}
break; //leaves the while loop
}
s.displayStack(); //displays the items on the stack
}
else if (nextChar == '/') //continues if next char is a /
{
sourceFile.get(nextChar); //gets the next character in file
if (nextChar == '*') //continues if next char is a *
{ //at this point a comment has started because of / then *
insideComment = true; //sets bool to true
newItem->token = 'c'; //sets newItem's token to c for "comment"
newItem->lineNumber = lineCount; //sets newItem's line count
s.push(newItem); //pushes the item onto the stack
while (insideComment == true && !sourceFile.eof())
{ //continues while inside a comment and end of file isn't reached
sourceFile.get(nextChar); //gets the next character in file
if (nextChar == '*') //continues if next char is *
{
sourceFile.get(nextChar); //gets the next character in file
if (nextChar == '/') //continues if next char is /
{ //at this point the comment has ended because of * then /
insideComment = false; //sets bool to false
s.pop(); //pops off the c in the stack
}
}
}
}
else if (nextChar == '/') //continues if next char is a /
{ //at this point a comment has started because of / then another /
insideComment = true; //sets bool to true
while (insideComment == true && !sourceFile.eof())
{ //continues while inside a comment and not at end of file
sourceFile.get(nextChar); //gets the next character in file
if (nextChar == '\n') //leaves comment if next line is entered
insideComment = false; //sets bool to false
}
}
}
else if (nextChar == '\n') //continues if next char is an end line
{
lineCount++; //increments line count
cout << "Line count: " << lineCount << endl; //echoes line count
}
else if (nextChar == '\"' && insideComment == false)
{ //continues if next char is a " and is not currently inside a comment
insideString = true; //sets bool to true b/c " starts a string
while (insideString == true && !sourceFile.eof())
{
sourceFile.get(nextChar); //gets the next character in file
if (nextChar == '\"')
insideString = false;
else if (nextChar == '\n')
{
lineCount++; //increments line count
cout << "Line count: " << lineCount << endl; //echoes line count
}
}
}
else if (nextChar == '\'' && insideComment == false && insideString == false)
{ //continues if next char is a ' and not in a comment or string
apostCount = 1; //initializes apostrophe count (chars after first apostrophe)
while (nextChar != '\'' && !sourceFile.eof())
{ //continues while next char isn't another ' and not end of file
sourceFile.get(nextChar); //gets the next character in file
apostCount++; //increments apostrophe count
if (nextChar == '\\') //continues if next char is a \
{
sourceFile.get(nextChar); //gets the next character in file
apostCount++; //increments apostrophe count
if (nextChar == '\'' && apostCount <= 3) //must be less than/= 3 spaces
nextChar = ' '; //sets next char to space if another apostrophe
}
else if (nextChar == '\n') //continues if next char is an end line
{
lineCount++; //increments line count
cout << "Line count: " << lineCount << endl; //echoes line count
}
}
if (apostCount >= 4) //if more than 3 chars come after apostrophe
{ //displays delimeter error
cout << "Character delimeter error on line " << lineCount << endl;
delimError = true;
break; //leaves while loop after displaying error
}
if (delimError == true) //continues if delimiter error occured
break; //leaves 2nd while loop
}
}
} //end of while loop
if (s.isEmpty() == false) //continues if no errors within stack
{ //displays successful nesting structure to user
cout << "Source file of " << lineCount << " lines has proper nesting structure";
cout << endl << endl << "Process another file? (y/n): "; //asks to continue
cin >> response; //gets user's response
while (response != 'y' && response != 'n') //checks for input error
{
cout << "Error! Must enter either y for yes or n for no." << endl;
cout << endl << endl << "Process another file? (y/n): ";
cin >> response; //gets user input
}
}
else //continues if errors are present
{
s.processStack(); //processes and displays the delimiter errors
cout << endl << endl << "Process another file? (y/n): "; //asks to continue
cin >> response; //gets user's response
while (response != 'y' && response != 'n') //checks for input error
{
cout << "Error! Must enter either y for yes or n for no." << endl;
cout << endl << endl << "Process another file? (y/n): ";
cin >> response; //gets user input
}
}
}
while (response == 'y'); //opens another file if user entered y for yes
return 0; //quits program
}
请帮助！
答案 0 :(得分：7)
下面：
if (nextChar == '\\') //continues if next char is a \
尾随\标记下一个当前行的延续。
您的下一行是{。
因此，在此条件之后的开头{被视为评论的一部分。
摘录：
if (nextChar == '\\') //continues if next char is a \
{
sourceFile.get(nextChar); //gets the next character in file
apostCount++; //increments apostrophe count
if (nextChar == '\'' && apostCount <= 3) //must be less than/= 3 spaces
nextChar = ' '; //sets next char to space if another apostrophe
}
被编译器视为
if (nextChar == '\\')
sourceFile.get(nextChar);
apostCount++;
if (nextChar == '\'' && apostCount <= 3)
nextChar = ' ';
}
所以你最后得到一个额外的}，这会让一切都变得混乱。