在的printf（QUOT;％D＆QUOT，5）;被存储在存储器5？ [英] In printf ( "%d", 5 ); is 5 stored in the memory?

问题描述

#include <stdio.h>
char* func ();
int main ( )
{
   char *p;
   p=func();
   printf("%c",*p);
}
char* func()
{

    return "hello";
}

下面，printf的打印h的，这意味着以你好，创建一个指针和该字符串你好被存储在存储器中。
同样地，在输出（％d个，5），是5存储在存储器

Here, printf prints "h", which means that a pointer to "hello" is created and that the string "hello" is stored in memory. Similarly, in printf ( "%d", 5 ), is '5' stored in the memory?

推荐答案

您的问题是非常依赖于平台，但大多数理智的编译器不应该存储 5 中的任何数据段您code，只有或阅读 - 它应该被简单地推的printf 调用之前堆栈上的

Your question is extremely platform dependent, but most sane compilers shouldn't store 5 in any data section of your code, read only or otherwise -- it should be simply pushed on the stack before the printf call.

编辑：我其实只是检查，GCC做更有趣的东西：

I actually just checked, and GCC does something even more interesting:

这完全避免了64位机上的堆栈，并使用可用的，因为众多的直寄存器。它仍然不存储 5 任何地方，但在OP code本身。

It avoids the stack entirely on a 64-bit machine and uses straight registers because of the multitude available. It still doesn't store the 5 anywhere but in the opcode itself.

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