小编Cra*_*ool的帖子

我是 C 初学者。当我尝试运行以下代码时：

#include <stdio.h>

    int main(void) {

    int a = 3, b;

    b = printf("%d %d", a, a++);
    a = printf(" %d", b);
    printf(" %d", a);

    return 0;
}

它向我展示：

error: operation on 'a' may be undefined [-Werror=sequence-point]
b = printf("%d %d", a, a++);
                        ^

但在这里我只改变了一次的值。那为什么会出现序列点错误呢？

我正在使用 -Wall -Werror 标志。

我是一个完整的菜鸟.我只是学习使用java编程.我按照教程在我兄弟的计算机上的IntelliJ Idea中创建了以下applet:

import javax.swing.JApplet;
import java.awt.Graphics;
public class MyFirstApplet extends JApplet {
    public void paint(Graphics g) {
        g.drawString("To climb a ladder, start at the bottom rung.", 20, 90);
    }
}

当我尝试运行它时,IDE显示:

"Exception in thread "main" java.security.AccessControlException: access denied ("java.io.FilePermission" "C:\Users\Abhirup_2\AppData\Local\Temp\AppletPage6525114136327939228.html" "read")
    at java.security.AccessControlContext.checkPermission(AccessControlContext.java:372)
    at java.security.AccessController.checkPermission(AccessController.java:559)
    at java.lang.SecurityManager.checkPermission(SecurityManager.java:549)
    at java.lang.SecurityManager.checkRead(SecurityManager.java:888)
    at java.io.File.isDirectory(File.java:838)
    at sun.net.www.protocol.file.FileURLConnection.connect(FileURLConnection.java:82)
    at sun.net.www.protocol.file.FileURLConnection.getInputStream(FileURLConnection.java:188)
    at sun.applet.AppletViewer.parse(AppletViewer.java:1103)
    at sun.applet.AppletViewer.parse(AppletViewer.java:1074)
    at sun.applet.Main.run(Main.java:156)
    at sun.applet.Main.main(Main.java:98)
    at sun.applet.AppletViewer.main(AppletViewer.java:1257)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)

Process finished with exit …