nodejs中的C scanf等价物 [英] C scanf equivalent in nodejs

问题描述

如果我想从 C 中的输入流中读取，我写 scanf 。， NodeJS中是否有等效方法做同样的事情？

If I want to read from the input stream in C I write scanf., Is there equivalent method in NodeJS to do the same?

例如，这里的代码是 C

int n,
    m,
    i;

scanf("%d", &n);

for (i = 0; i < n; i++) {
    scanf("%d", &m);

    ............

}

这是我从Node开始的地方... TODO 表示我被困的地方：

Here's where I'm starting from in Node... TODO indicates where I'm stuck:

process.stdin.resume();
process.stdin.setEncoding("ascii");

process.stdin.on("data", function (input) {
    var n = +input;
    for (var i = 0; i < n; i++) {
        // TODO
    }
});

推荐答案

对于初学者，请致电 scanf 和NodeJS中可读流的数据事件不等效。在NodeJS示例中，您将需要解析您收到的输入的块。

For starters, calling scanf and the data event for a readable stream in NodeJS are not equivalent. In the NodeJS example, you will need to parse the chunk of the input you've received.

您可以通过替换以下内容来检查这些块的发送方式。你的on方法很简单：

You can examine how these chunks are sent to you by replacing the body of your on method with a simple:

process.stdout.write('onData: ' + input + '\n');

鉴于如何输入然后包含你的数据你我需要使用一些方法来提取感兴趣的字符串，然后使用 parseInt 。假设你的问题很简单，假设每个输入为1个整数：

Given how input then contains your data you'll need to use some method to extract the string of interest and then use parseInt. Perhaps a naive approach to your problem, assuming 1 integer per input:

var n = 0;
var m = 0;
var state = 0;
process.stdin.on('data', function (input) {
    switch (state)
    {
    case 0:
        // we're reading 'n'
        n = parseInt(input.trim(), 10);
        state++;
        break;

    default:
        // we're reading 'm'
        m = parseInt(input.trim(), 10);

        if (state++ == n)
        {
            // we've read every 'm'
            process.exit();
        }
        break;
    }
});

我不是这种将数据传递到NodeJS事件循环的非常大的粉丝，你应改为查看命令行参数，配置/输入文件或其他方法。

I'm not a terribly large fan of this means of getting data to your NodeJS event loop, you should instead look to command line arguments, configuration/input files, or some other means.

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