說起來很有意思,自認為對C語言理解得還是比較深刻的。但居然到今天才知道有個strtok函數,試用了一下突然感慨以前做了多少重復勞動。每次需要解析配置文件,每次需要分割字符串,居然都是自己去分割字符串,既累人又容易出錯。感概繼續學得不夠全面啊!這里引用一段strtok用法:
The strtok() function returns a pointer to the next "token" in str1, where str2 contains the delimiters that determine the token. strtok() returns NULL if no token is found. In order to convert a string to tokens, the first call to strtok() should have str1 point to the string to be tokenized. All calls after this should have str1 beNULL.
For example:
char str[] = "now # is the time for all # good men to come to the # aid of their country";
char delims[] = "#";
char *result = NULL;
result = strtok( str, delims );
while( result != NULL ) {
printf( "result is \"%s\"\n", result );
result = strtok( NULL, delims );
}
The above code will display the following output:
result is "now "
result is " is the time for all "
result is " good men to come to the "
result is " aid of their country"
這個函數跟編譯器中的詞法分析很向,在以后的文本處理中,會解決很多問題。看來我有必要系統的學習下C的庫函數,而不僅僅是死扎在語法和一些算法技巧上面。這樣在平常的工作中才能事半功倍。
使用這個函數,形如下面得配置文件就非常容易解析:
id1 value1 value2 value3
id2 value1 value2 value3
...
使用這個函數,分割字符串就更加方便了,例如下面待分割的字符串:
12|2345|asld|alsfalskd
只要讀取待處理的數據,然后調用四次strtok就能夠解析出每行的值,以前我一般不是自己解析就是用sscanf,但是strtok更加合適,也更加啊靈活!