Question

从命令行，我想编写一个for循环，它将从命令行参数中检测数组中是否有字符串或char。

例如，某人输入4.3, 5, 99, 0.1, w, 4, 2.43。当循环检测到char w时，它将打印“Error”。如果输入为4.3, 5, 99, 0.1, wasabi, 4, 2.43，则同样如此;当循环检测到字符串wasabi时，它将显示错误消息。我无法弄清楚的是如何编写循环以便它检测任何字符或字符串，无论它在数组中的哪个位置。这就是我到目前为止所做的：

//check for a string or char in array
void checkForWord(int argc, char* argv[])
{
    for (int i = 1; i < argc - 1; i++)
    {
        if ()
        {
            //do something..
        }
    }
}

任何帮助都将非常感谢!!

Answer 1

可能是这样的：

for (int i = 1; i < argc; i++)  // Don't do argc - 1 when using <
{
    string s = argv[i];
    for (auto c : s)
    {
        if (c != ',' && c != '.' && !isdigit(c))
        {
            cout << "Error" << endl;
            return;
        }
    }
}

注意：这会接受4....3,,,,, 5, 99, 0.1, 4, 2.43之类的输入，因为代码不会检查.的数量和,的数量

Answer 2

你走了。完整的工作示例：

#include <iostream>
#include <string>
#include <algorithm>
#include <sstream>

int main(int argc, const char* const* argv)
{
    // first, concatenate the command line arguments into a continuous buffer
    std::string buffer;
    auto sep = "";
    for(int i = 1 ; i < argc ; ++i)
    {
        buffer += sep;
        buffer += argv[i];
        sep = " ";
    }

    // now turn the buffer into a string stream
    auto stream = std::istringstream(buffer);

    // now stream in my numbers, delimited by commas
    std::string val_buffer;
    while (std::getline(stream, val_buffer, ','))
    {
        // make a new string stream, just to parse the text into a number
        auto num_stream = std::istringstream(val_buffer);
        double val = 0;
        if (num_stream >> val)
        {
            // parsed correctly. now let's do something with it
            std::cout << "found a value: " << val << std::endl;
        }
        else 
        {
            // whatever that was, it wasn't a number
            std::cout << "found a something I didn't like: " << val_buffer << std::endl;
            break;
        }
    }

    if (stream.bad())
    {
        std::cout << "something bad happened" << std::endl;
    }
    return 0;
}

使用命令行4.3, 5, 99, 0.1, wasabi, 4, 2.43执行时

结果：

found a value: 4.3
found a value: 5
found a value: 99
found a value: 0.1
found a something I didn't like:  wasabi

没有芥末的结果：

found a value: 4.3
found a value: 5
found a value: 99
found a value: 0.1
found a value: 4
found a value: 2.43

如何检查数组的字符串或字符

2 个答案: