我们先来看看下面的代码：
#include<iostream>
#include<fstream>
#include<cstdlib>
using namespace std;
class CntCharacters
{
private:
int cnt;
public:
CntCharacters():cnt(0){}
~CntCharacters(){}
void opentxt(char* p)
{
ifstream fin;
fin.open(p,ios_base::in);
if(!fin.is_open())
{
cout<<"cannot open the file,Please make sure the file is exist!\n";
exit(-1);
}
char temp;
while(!fin.eof())
{
fin>>temp;
if((temp>='a'&&temp<='z')||(temp>='A'&&temp<='Z'))cnt++;
}
}
void countthecharacter()
{
int count=0;
char nameoffile[80];
cout<<"Please enter the name of file:";
cin>>nameoffile;
// scanf("%s",nameoffile);
opentxt(nameoffile);
}
void dis()
{
cout<<cnt<<endl;
}
};
int main()
{
CntCharacters* c=new CntCharacters;
c->countthecharacter();
c->dis();
delete c;
return 0;
}
网上大神的简单代码
#include<iostream>
#include<fstream>
using namespace std;
int main()
{
fstream f("test.txt",ios::in);
char c;
int n=0;
while(f.get(c))n++;
cout<<n<<endl;
f.close();
return 0;
}
上面那方法会计算空格和换行，如果不想要换行和空格，可以这样:
#include<iostream>
#include<fstream>
using namespace std;
int main()
{
fstream f("test.txt",ios::in);
char c;
int n=0;
while(f>>c)n++;
cout<<n<<endl;
f.close();
return 0;
}
好了，最后来看一下项目中使用到的代码
//countch.cpp
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main(int argc, char* argv[])
{
ifstream fin(argv[1]);
if (!fin) {
cout << "Can't open file - " << argv[1]
<< "\nUseage : countch filename" << endl;
return 1;
}
string d;
int count = 0;
while ( getline(fin, d) ) //以行为单位读入文件
count += d.size(); //累计字符数
cout << "\n Number of characters : "<< count << endl;
}