Question

C++计算文件中单词的个数

// wenjian.cpp : 定义控制台应用程序的入口点。
#include "stdafx.h"
#include<string>
#include<iostream>
#include<fstream>
#include<vector>
using namespace std;
int _tmain(int argc, _TCHAR* argv[])
{
int i,word=0;
int num=0;
char c;
vector<char> v;
ifstream in("wenjian.cpp");

for (i = 0; (c = v[i]) != '\0'; i++)
{
if (c == ' ')
word = 0;
else
if (word == 0)
{
word = 1;
num++;
}
}
cout<<"\nThere are %d words int the line.\n"<< num<<endl;

return 0;
}
调试可以通过，一运行及出错

Answer 1

char c;
vector<char> v;
ifstream in("wenjian.cpp");

for (i = 0; (c = v[i]) != '\0'; i++)//你这里v[i]的值都没初始化,怎么可能不错啊?你得先把文件的内容读入这个vector
__________________________________________________
按照你的思路给你改了
#include<string>
#include<iostream>
#include<fstream>
#include<vector>
#define _TCHAR char
using namespace std;
int main(int argc, _TCHAR* argv[])
{
int i,word=0;
int num=0;
char c;
vector<char> v;
ifstream in("wenjian.cpp");
while((c=in.get())!=EOF) //这里将文件内容读入容器
v.push_back(c);
v.push_back('\0'); //最后得加上'\0'标识
for (i = 0; (c = v[i]) != '\0'; i++)
{
if (c == ' '||c=='\n') //这里增加回车
word = 0;
else
if (word == 0)
{
word = 1;
num++;
}
}
cout<<"\nThere are "<<num<<" words int the line.\n"<<endl;

return 0;
}

Answer 2

你对向量v都没初始化啊
#include<stdafx.h>
#include<string>
#include<iostream>
#include<fstream>
#include<vector>
using namespace std;
int main()
{
int i,word=0;
int num=0;
char c;
vector<char> v;
ifstream in("wenjian.cpp");
char ch[100]={0};
in.read(ch,100);
for(int t=0;t<strlen(ch)-1;t++)
{
v.push_back(ch[t]);
}

for (i = 0; (c = v[i]) != '\0'; i++)
{
if (c == ' '||c=='\n')
word = 0;
else
if (word == 0)
{
word = 1;
num++;
}
}
cout<<"There are "<< num<<" words the line"<<endl;

return 0;
}

Answer 3

#include<stdio.h>
#include<ctype.h>
#define STOP '|'
int main(void)
{
char c;
char prev;
long n_chars = 0L;
int n_lines = 0;
int n_words = 0;
int p_lines = 0;
int inword = 0;

printf("Enter text to be analyzed( | to be quit):\n ");
prev = '\n';
while((c = getchar()) != STOP)
{
n_chars++;
if (c == '\n')
n_lines++;
if (!isspace(c) && !inword)
{
inword = 1;
n_words++;

}
if(isspace (c) && inword)
inword = 0;
prev = c;
}

if(prev != '\n')
p_lines = 1;
printf("characters = %ld,word = %d,line = %d,",
n_chars,n_words,n_lines);
printf("partial lines = %d\n",p_lines);
return 0;

}
prev 是一个字符变量，用于检查是否到了一行的末尾。 这个例子不是很难，用#define是为了增加程序的可修改性，你可以只看关键的方法部分也就是如何计算单词数和行数。这种符合标准的程序应该多看看，有好处，像这些C语言算法都不算什么，为的就是学习编程的标准和语法，根本涉及不到算法呢，呵呵。
isspace (c)检查参数c是否为空格字符，也就是判断是否为空格('')、定位字符
('\t')、CR('\r')、换行('\n')、垂直定位字符('\v')或翻页('\f')的情况。
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