Turns out, Linux Number 1-Linux,Linux always order programming-IT news Turns out, Linux was always Number 1
Hi, I'm writing a simple program, I want to let this program prints out a whole number.
#include
int main() {
int linux = 701;
printf("%d", linux);
return 0;
}
Simple enough. : Really?
I put it into the code.c
I now compile and run it:
$ gcc code.c && ./a.out
Bad! Compile failed, and receive the following error message:
code.c: In function'main':
code.c:4:6: error: expected identifier or'('before numeric constant
int linux = 701;
^
Confusing!!
After Googling this error information – this is the error code needs to be preprocessed.
So, I bring the-e argument at compile time, it can compile stops after preprocessing:
$ gcc -E code.c
Preprocessed main () function code appears as follows:
int main() {
int 1 = 701;
printf("%d\n", 1);
return 0;
}
I passed out! C-language editor of preprocessing Linux changed the variable the integer 1. When the compiler encounters an int 1=701; statement, throws an error.
Now, I'm no Linux assign any values to variables:
#include
int main() {
printf("%d\n", linux);
return 0;
}
To compile and run:
$ gcc code.c && ./a.out
It compiles successfully and the output:
1
Turns out, Linux is Number1
(
事实证明，Linux总是Number 1 - Linux,Linux命令,编程 - IT资讯
事实证明，Linux总是Number 1
嗨，我正在写一个简单的程序，我要让这个程序打印出一个整数。
#include
int main() {
int linux = 701;
printf("%d", linux);
return 0;
}
够简单吧。真的吗？
我把它存成了code.c
现在我编译并运行它：
$ gcc code.c && ./a.out
糟糕！，编译失败，出现了下面的错误信息：
code.c: In function‘main’:
code.c:4:6: error: expected identifier or‘(’before numeric constant
int linux = 701;
^
困惑!!
在谷歌上搜索这个错误——得到的信息是这种错误需要对代码进行预处理。
于是，我在编译时带上了-E参数，它能让编译在预处理后停止：
$ gcc -E code.c
预处理过的main()函数代码显示如下：
int main() {
int 1 = 701;
printf("%d\n", 1);
return 0;
}
我晕！C语言的预处理编辑器竟然将变量linux换成了整数1。当编译器遇到了int 1 = 701;语句时，抛出了错误。
现在，我不对变量linux赋任何值：
#include
int main() {
printf("%d\n", linux);
return 0;
}
编译并运行：
$ gcc code.c && ./a.out
编译成功并且输出：
1
事实证明，linux总是Number1
)
