准确读入一或两个字符串

发布于 2024-11-04 12:18:31 字数 506 浏览 0 评论 0原文

我有一个程序接受来自命令行的输入。虽然所有可用命令都是一个字符串，但其中一些命令需要辅助字符串来进一步定义操作。

例如，“end”是一个命令，“add foo”是第二个命令。

我的代码可以很好地处理 2 个字符串输入，但是当我尝试访问单个字符串命令（例如“end”）时，程序会等待更多输入，而不是立即执行操作。

有什么方法可以让程序只读取一行（最多可能有两个字符串）而不是像现在这样？

目前的实施方式如下：

while(1)
    {
        scanf("%s%s", commandString,floorPath);

            if(!strcmp(commandString,"end") return;
            //I've got several of these as an "if / else", but there's no
            //need to reprint them here.

    }

原文

I have a program that accepts input from the command line. While all of the available commands are one string, several of the commands require a secondary string to further define the action.

e.g. "end" is one command, and "add foo" is a second.

My code handles the 2 string inputs fine, but when I try to access a single string command (such as "end") the program waits for more input instead of acting immediately.

Is there some way I can get the program to read in exactly one line (which may have up to two strings) rather than the way it is now?

Here's how it's currently implemented:

while(1)
    {
        scanf("%s%s", commandString,floorPath);

            if(!strcmp(commandString,"end") return;
            //I've got several of these as an "if / else", but there's no
            //need to reprint them here.

    }

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有深☉意 2024-11-11 12:22:26

这是一个替代方案：

int cmdFromStdin (char **cmd) {
    int count = 0, nBytes = 0;
    char *word, inline[BUFSIZ];

    if (nBytes = getline (inline, BUSIZ, STDIN)) < 0)
        return nBytes;
    for (word = strtok (inline, " ") ; word != NULL ; 
                    word = strtok (NULL, " "))
        cmd[count++] = word;
    return count;
}

自从我用 C 编码以来已经有一段时间了，但我记得 scanf 遇到了问题（所以我曾经使用 getline()）。 strtok 函数将解析出字符串，返回时您可以检查是否成功并处理数组 cmd。我相信你必须为此包含 stdio.h、stdlib.h 和 string.h。我的C有点生疏，所以请原谅语法错误。

Here is an alternative:

int cmdFromStdin (char **cmd) {
    int count = 0, nBytes = 0;
    char *word, inline[BUFSIZ];

    if (nBytes = getline (inline, BUSIZ, STDIN)) < 0)
        return nBytes;
    for (word = strtok (inline, " ") ; word != NULL ; 
                    word = strtok (NULL, " "))
        cmd[count++] = word;
    return count;
}

It's been a while since I have coded in C, but I remember having problems with scanf (so I used to use getline()). The strtok function will parse out the string, on return you can check for success and work on the array cmd. I believe you have to include stdio.h, stdlib.h and string.h for this. My C is a bit rusty, so please excuse the syntax errors.

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爱情眠于流年 2024-11-11 12:22:15

MByD 所说的，或者，读取一行，然后与 scanf() 分开解析您读入的行，看看它是一个字命令还是两个字命令，并采取适当的方法行动。

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蓝天白云 2024-11-11 12:21:41

单独读取第一个字符串，并根据输入决定是否需要读取另一个字符串。

while(1)
{
    scanf("%s", commandString);
    if (requiresAnotherString(commandString))
    {
         scanf("%s", floorPath);
         // handle two string command
    }
    else
    {
         // handle one string command
    }
}

Read the first string alone, and depending on the input decide if there is a need to read another string or not.

while(1)
{
    scanf("%s", commandString);
    if (requiresAnotherString(commandString))
    {
         scanf("%s", floorPath);
         // handle two string command
    }
    else
    {
         // handle one string command
    }
}

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