用以下程序舉例：

#include <iostream>
/*
* 注釋對 /* */ 不能嵌套
* 否則后面的字會被認為是源碼，像剩余程序一樣處理
*/

int main() {
    return 0;
}

命名為 exa.cpp，然后編譯這個程序。

# g++ exa.cpp
exa.cpp:4:17: error: stray ‘\344’ in program
 * 注釋對/* */不能嵌套
                 ^
exa.cpp:4:17: error: stray ‘\270’ in program
exa.cpp:4:17: error: stray ‘\215’ in program
exa.cpp:4:17: error: stray ‘\350’ in program
exa.cpp:4:17: error: stray ‘\203’ in program
exa.cpp:4:17: error: stray ‘\275’ in program
exa.cpp:4:17: error: stray ‘\345’ in program
exa.cpp:4:17: error: stray ‘\265’ in program
exa.cpp:4:17: error: stray ‘\214’ in program
exa.cpp:4:17: error: stray ‘\345’ in program
exa.cpp:4:17: error: stray ‘\245’ in program
exa.cpp:4:17: error: stray ‘\227’ in program
exa.cpp:5:1: error: stray ‘\342’ in program
 * “不能嵌套”幾個字會被認為是源碼，像剩余程序一樣處理
 ^
exa.cpp:5:1: error: stray ‘\200’ in program
exa.cpp:5:1: error: stray ‘\234’ in program
exa.cpp:5:1: error: stray ‘\344’ in program
exa.cpp:5:1: error: stray ‘\270’ in program
exa.cpp:5:1: error: stray ‘\215’ in program
exa.cpp:5:1: error: stray ‘\350’ in program
exa.cpp:5:1: error: stray ‘\203’ in program
exa.cpp:5:1: error: stray ‘\275’ in program
exa.cpp:5:1: error: stray ‘\345’ in program
exa.cpp:5:1: error: stray ‘\265’ in program
exa.cpp:5:1: error: stray ‘\214’ in program
exa.cpp:5:1: error: stray ‘\345’ in program
exa.cpp:5:1: error: stray ‘\245’ in program
exa.cpp:5:1: error: stray ‘\227’ in program
exa.cpp:5:1: error: stray ‘\342’ in program
exa.cpp:5:1: error: stray ‘\200’ in program
exa.cpp:5:1: error: stray ‘\235’ in program
exa.cpp:5:1: error: stray ‘\345’ in program
exa.cpp:5:1: error: stray ‘\207’ in program
exa.cpp:5:1: error: stray ‘\240’ in program
exa.cpp:5:1: error: stray ‘\344’ in program
exa.cpp:5:1: error: stray ‘\270’ in program
exa.cpp:5:1: error: stray ‘\252’ in program
exa.cpp:5:1: error: stray ‘\345’ in program
exa.cpp:5:1: error: stray ‘\255’ in program
exa.cpp:5:1: error: stray ‘\227’ in program
exa.cpp:5:1: error: stray ‘\344’ in program
exa.cpp:5:1: error: stray ‘\274’ in program
exa.cpp:5:1: error: stray ‘\232’ in program
exa.cpp:5:1: error: stray ‘\350’ in program
exa.cpp:5:1: error: stray ‘\242’ in program
exa.cpp:5:1: error: stray ‘\253’ in program
exa.cpp:5:1: error: stray ‘\350’ in program
exa.cpp:5:1: error: stray ‘\256’ in program
exa.cpp:5:1: error: stray ‘\244’ in program
exa.cpp:5:1: error: stray ‘\344’ in program
exa.cpp:5:1: error: stray ‘\270’ in program
exa.cpp:5:1: error: stray ‘\272’ in program
exa.cpp:5:1: error: stray ‘\346’ in program
exa.cpp:5:1: error: stray ‘\230’ in program
exa.cpp:5:1: error: stray ‘\257’ in program
exa.cpp:5:1: error: stray ‘\346’ in program
exa.cpp:5:1: error: stray ‘\272’ in program
exa.cpp:5:1: error: stray ‘\220’ in program
exa.cpp:5:1: error: stray ‘\347’ in program
exa.cpp:5:1: error: stray ‘\240’ in program
exa.cpp:5:1: error: stray ‘\201’ in program
exa.cpp:5:1: error: stray ‘\357’ in program
exa.cpp:5:1: error: stray ‘\274’ in program
exa.cpp:5:1: error: stray ‘\214’ in program
exa.cpp:5:1: error: stray ‘\345’ in program
exa.cpp:5:1: error: stray ‘\203’ in program
exa.cpp:5:1: error: stray ‘\217’ in program
exa.cpp:5:1: error: stray ‘\345’ in program
exa.cpp:5:1: error: stray ‘\211’ in program
exa.cpp:5:1: error: stray ‘\251’ in program
exa.cpp:5:1: error: stray ‘\344’ in program
exa.cpp:5:1: error: stray ‘\275’ in program
exa.cpp:5:1: error: stray ‘\231’ in program
exa.cpp:5:1: error: stray ‘\347’ in program
exa.cpp:5:1: error: stray ‘\250’ in program
exa.cpp:5:1: error: stray ‘\213’ in program
exa.cpp:5:1: error: stray ‘\345’ in program
exa.cpp:5:1: error: stray ‘\272’ in program
exa.cpp:5:1: error: stray ‘\217’ in program
exa.cpp:5:1: error: stray ‘\344’ in program
exa.cpp:5:1: error: stray ‘\270’ in program
exa.cpp:5:1: error: stray ‘\200’ in program
exa.cpp:5:1: error: stray ‘\346’ in program
exa.cpp:5:1: error: stray ‘\240’ in program
exa.cpp:5:1: error: stray ‘\267’ in program
exa.cpp:5:1: error: stray ‘\345’ in program
exa.cpp:5:1: error: stray ‘\244’ in program
exa.cpp:5:1: error: stray ‘\204’ in program
exa.cpp:5:1: error: stray ‘\347’ in program
exa.cpp:5:1: error: stray ‘\220’ in program
exa.cpp:5:1: error: stray ‘\206’ in program
exa.cpp:6:2: error: expected unqualified-id before ‘/’ token
 */
  ^
exa.cpp:6:2: error: expected constructor, destructor, or type conversion before ‘/’ token

輸出的報錯...

如果不是已經(jīng)知道了問題才看到報錯，而是要從報錯反推問題，實在會讓人束手無策。

究其原因就是注釋對 “/* */” 不可嵌套，“/*” 總會與后文遇到的第一個 “*/” 組成一對，“*/” 總會與前文最近的 “/*” 組成一對。

當然這是指每行都不存在分號的情況下，如果有分號，這一行不論遇到了什么都結(jié)束了。

幾個例子：

cout << "/*";                  // 輸出“/*”
cout << "*/";                  // 輸出“*/”
cout << /* "*/" /* "/*" */;    // 輸出“ /* ”

PS. 今天收到了簡書送來的禮物，是一本宋詞書，haha。那么以后只要有 idea 我就來更一波~