我的文本文件包含一些列
getline();我知道我可以使用{{1}}访问一行，但是当我获得带有{{1}}返回的数据的字符串时，我想阅读一些特定的列。我该怎么做？
我看到了这个问题的解决方案但它在java中我还不知道，所以我决定将其发布为c ++答案
答案 0 :(得分：1)
方法是相同的：逐行读取文件并使用tokenize，如果我想看第二列，则取数组的第二个elem。 它可以改进，因为它有很多副本，但想法就在这里。
message "Servlet.init()" pour la servlet AxisServlet a généré une exception
description Le serveur a rencontré une erreur interne qui l''a empêché de satisfaire la requête.
exception
javax.servlet.ServletException: "Servlet.init()" pour la servlet AxisServlet a généré une exception
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
cause mère
java.lang.ExceptionInInitializerError
org.apache.axis2.transport.http.AxisServlet.initConfigContext(AxisServlet.java:620)
org.apache.axis2.transport.http.AxisServlet.init(AxisServlet.java:471)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
cause mère
org.apache.commons.logging.LogConfigurationException: org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException) (Caused by org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException))
org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:543)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
org.apache.axis2.deployment.DeploymentEngine.<clinit>(DeploymentEngine.java:70)
org.apache.axis2.transport.http.AxisServlet.initConfigContext(AxisServlet.java:620)
org.apache.axis2.transport.http.AxisServlet.init(AxisServlet.java:471)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
cause mère
org.apache.commons.logging.LogConfigurationException: java.lang.NullPointerException (Caused by java.lang.NullPointerException)
org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:397)
org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
org.apache.axis2.deployment.DeploymentEngine.<clinit>(DeploymentEngine.java:70)
org.apache.axis2.transport.http.AxisServlet.initConfigContext(AxisServlet.java:620)
org.apache.axis2.transport.http.AxisServlet.init(AxisServlet.java:471)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
cause mère
java.lang.NullPointerException
org.apache.commons.logging.impl.LogFactoryImpl.getLogConstructor(LogFactoryImpl.java:374)
org.apache.commons.logging.impl.LogFactoryImpl.newInstance(LogFactoryImpl.java:529)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:235)
org.apache.commons.logging.impl.LogFactoryImpl.getInstance(LogFactoryImpl.java:209)
org.apache.commons.logging.LogFactory.getLog(LogFactory.java:351)
org.apache.axis2.deployment.DeploymentEngine.<clinit>(DeploymentEngine.java:70)
org.apache.axis2.transport.http.AxisServlet.initConfigContext(AxisServlet.java:620)
org.apache.axis2.transport.http.AxisServlet.init(AxisServlet.java:471)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:505)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:956)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:442)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1082)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:623)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
答案 1 :(得分：1)
无论你是用Java还是C ++，这种方法都是类似的。
阅读完整行后。用分隔符分割线。
在Java中，它只是
set_property PACKAGE_PIN <pin> [get_ports {segt[7]}]
set_property IOSTANDARD LVCMOS33 [get_ports {segt[7]}]
在C ++中，您可以使用line.split(",");
来获取逗号的位置。然后将分隔的标记子串出来。
设置一个str.find(",")变量来计算到目前为止已分隔的令牌数量，以便到达您想要的列。
答案 2 :(得分：0)
您也可以使用strtok解析C字符串（如果您使用STL字符串，请将C字符串复制到char数组！）。它可以很好地工作，虽然需要一个单独的副本是由于strtok确实修改了字符串以及一些静态内存（或者，也许是线程本地存储;我不会依赖它）