C++ 教程目录

输入、输出和文件

count.cpp

来源: 输入、输出和文件

点击上方按钮打开代码编辑器和可视化视图

⚠️ 交互式运行提示

为了防止网页挂起,所有 cin 输入语句已被自动注释。请直接在代码编辑器中修改变量的值来进行测试。

书本配套例题

原始代码预览

// count.cpp -- counting characters in a list of files
#include <iostream>
#include <fstream>
#include <cstdlib>          // or stdlib.h
int main(int argc, char * argv[])
{
    using namespace std;
    if (argc == 1)          // quit if no arguments
    {
        cerr << "Usage: " << argv[0] << " filename[s]\n";
        exit(EXIT_FAILURE);
    }

    ifstream fin;              // open stream
    long count;
    long total = 0;
    char ch;

    for (int file = 1; file < argc; file++)
    {
        fin.open(argv[file]);  // connect stream to argv[file]
        if (!fin.is_open())
        {
            cerr << "Could not open " << argv[file] << endl;
            fin.clear();
            continue;
        }
        count = 0;
        while (fin.get(ch))
            count++;
        cout << count << " characters in " << argv[file] << endl;
        total += count;
        fin.clear();           // needed for some implementations
        fin.close();           // disconnect file
    }
    cout << total << " characters in all files\n";

    return 0; 
}
C++ Playground
运行结果 / 调试信息
等待编译...
Graph loading...
0 / 0