小编bui*_*ude的帖子

我是android编程的新手.我指的是google开发者网站,以学习android.当我运行应用程序UI时,我遇到了这些错误.

 H:\SDK\tools\emulator.exe -avd Nexus_5_API_21_x86 -netspeed full -netdelay none
 emulator: ERROR: Could not initialize OpenglES emulation, use '-gpu off' to   disable it.
 could not get wglGetExtensionsStringARB
 could not get wglGetExtensionsStringARB
 could not get wglGetExtensionsStringARB
 could not get wglGetExtensionsStringARB
 could not get wglGetExtensionsStringARB
 could not get wglGetExtensionsStringARB
 could not get wglGetExtensionsStringARB
 could not get wglGetExtensionsStringARB
 getGLES1ExtensionString: Could not find GLES 1.x config!
 Failed to obtain GLES 1.x extensions string!
 Could not initialize emulated framebuffer

我正在使用android studio.

<?php  
function factorial_of_a($n)  
{  
    if($n ==0)  
    {  
        return 1;  
    }
    else   
    {    
        return $n * factorial_of_a( $n - 1 );  
    }  
}  
print_r( factorial_of_a(5) );
?>  

我的疑问是:

return $n * factorial_of_a( $n - 1 ) ;

在这个陈述中 - 它给出了20 $n = 5和/ 的结果$n - 1 = 4.但是当我运行时,答案120怎么样？嗯,120是正确答案......我不明白它是如何运作的.我使用了for-loop而且工作正常.