我发现添加一段时间的正确方法，所以我可以完成这个练习。但是，有两件事需要触摸。文件输出显示两次。第一次正确，第二次在一行（我不需要这一行显示）。第二个问题是account ++函数。它必须显示7个单词的计数，但它的计数为8。为什么？你能帮帮我吗？问题出在最后一刻。
#include<iostream>
#include<fstream>//step#1
#include<string>
using namespace std;
int main()
{
string word, fileName;
int charcounter = 0, wordcounter = 0;
char character;
ifstream inData;// incoming file stream variable
cout << " Enter filename or type quit to exit: ";
cin >> fileName;
//loop to allow for multiple files data reads
while (fileName != "quit")
{
inData.open(fileName.c_str());//open file and bind file to ifstream variable
//loop for file not found validation
while (!inData)//filestream is in fail state due to no file
{
inData.clear();//clear the fail state
cout << "File not found. Enter the correct filename: ";
cin >> fileName;
inData.open(fileName.c_str());
}
inData >> character;//extract a single character from the file
cout << "\n*****************************\n";
while (inData)
{
cout << character;
inData.get(character);//extract the next character and the next character
charcounter++;
}
//Here is the loop that is missing something
//I was told to close the file
inData.close();
//open up the file again and add the while loop
inData.open(fileName.c_str());
while (inData)
{
cout << word;
inData >> word;//extract the next word and the next word
wordcounter++;
}
cout << "\n******************************\n";
cout << fileName << " has " << wordcounter << " words" << endl;
inData.close();//close the ifstream conection to the data file
charcounter = 0; //reset char and word counts
wordcounter = 0;
//port for next file or exit
cout << "Enter a filename or type quit to exit: ";
cin >> fileName;
}
return 0;
}
您获得冗余输出的原因是您输出文件的内容两次，例如
第39-43行
while (inData)
{
cout << character;
...
第57-61行
while (inData)
{
cout << word;
...
无论是逐字符输出还是逐字输出，都要输出文件的内容。在一个循环中逐个字符地执行它，然后在另一个循环中逐个字符地执行它会导致输出的两倍。
此外，不需要循环文件两次来计算字符然后单词 - 在一个循环中完成所有操作，例如
int charcounter = 0,
wordcounter = 0,
inword = 0; /* flag indicating reading chars in word */
...
while (inData.get(character)) { /* read each character in file */
if (isspace (character)) /* if character is whitespace */
inword = 0; /* set inword flag zero */
else { /* if non-whitespace */
if (!inword) /* if not already in word */
wordcounter++; /* increment wordcounter */
inword = 1; /* set inword flag 1 */
}
charcounter++; /* increment charcounter */
}
您遇到的其余问题仅仅是由于您尝试使用的混乱循环逻辑，能够打开不同的文件，直到用户键入"quit"。您只需要一个外循环，它将不断循环，直到用户键入"quit"。您不需要对文件名进行多次检查和多次提示。只需使用一个循环，例如
for (;;) { /* loop continually until "quit" entered as fileName */
string word, fileName; /* fileName, character, inData are */
char character; /* only needed within loop */
int charcounter = 0,
wordcounter = 0,
inword = 0; /* flag indicating reading chars in word */
ifstream inData;
cout << "\nEnter filename or type quit to exit: ";
if (!(cin >> fileName)) { /* validate every read */
cerr << "(error: fileName)\n";
return 1;
}
if (fileName == "quit") /* test for quit */
return 0;
inData.open (fileName); /* no need for .c_str() */
if (!inData.is_open()) { /* validate file is open */
cerr << "error: unable to open " << fileName << '\n';
continue;
}
... /* the read loop goes here */
inData.close(); /* closing is fine, but will close at loop end */
cout << '\n' << fileName << " has " << wordcounter << " words and "
<< charcounter << " characters\n";
}
进行这些更改可以清理程序流程并使循环逻辑变为直接。总而言之，你可以做到：
#include <iostream>
#include <fstream>
#include <string>
#include <cctype>
using namespace std;
int main (void) {
for (;;) { /* loop continually until "quit" entered as fileName */
string word, fileName; /* fileName, character, inData are */
char character; /* only needed within loop */
int charcounter = 0,
wordcounter = 0,
inword = 0; /* flag indicating reading chars in word */
ifstream inData;
cout << "\nEnter filename or type quit to exit: ";
if (!(cin >> fileName)) { /* validate every read */
cerr << "(error: fileName)\n";
return 1;
}
if (fileName == "quit") /* test for quit */
return 0;
inData.open (fileName); /* no need for .c_str() */
if (!inData.is_open()) { /* validate file is open */
cerr << "error: unable to open " << fileName << '\n';
continue;
}
while (inData.get(character)) { /* read each character in file */
if (isspace (character)) /* if character is whitespace */
inword = 0; /* set inword flag zero */
else { /* if non-whitespace */
if (!inword) /* if not already in word */
wordcounter++; /* increment wordcounter */
inword = 1; /* set inword flag 1 */
}
charcounter++; /* increment charcounter */
}
inData.close(); /* closing is fine, but will close at loop end */
cout << '\n' << fileName << " has " << wordcounter << " words and "
<< charcounter << " characters\n";
}
}
示例输入文件
$ cat ../dat/captnjack.txt
This is a tale
Of Captain Jack Sparrow
A Pirate So Brave
On the Seven Seas.
示例使用/输出
$ ./bin/char_word_count
Enter filename or type quit to exit: ../dat/captnjack.txt
../dat/captnjack.txt has 16 words and 76 characters
Enter filename or type quit to exit: quit
与wc确认
$ wc ../dat/captnjack.txt
4 16 76 ../dat/captnjack.txt
仔细看看，如果您有其他问题，请告诉我。