63 lines
2.0 KiB
C
63 lines
2.0 KiB
C
/*
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Program: tokenization.c (Report comments/bugs to chikh@yuntech.edu.tw)
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Function: 輸入運算相關的文字串，從中提取關鍵資訊，為作業的預備暖身
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Notes: 輸入可為
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w={"Mary":10, "Tom":3, "Charlie":5, "Bob":6, "Dickens":20, 4:9, "z":0, "Za":12, "aZ":8}
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del w["Dickens"]
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w["Mary"]=1
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w["Tom"]+=2
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w[4]?
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w?
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*/
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#include <stdio.h> /* for sscanf(), printf() */
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#include <string.h> /* for strstr(), strtok(), strtok_r() */
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int main()
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{
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char *token, key[12], line[128];
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const char *s = " ={},"; /* 分隔符記的字元 */
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int value, i = 0;
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char *rest;
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printf("\n*** 從字串讀取符記(token)程式 ***\n\n輸入存取字典的陳述，逕按<Enter>結束程式\n");
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while (1) {
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printf("\n指令 => ");
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fgets(line,128,stdin); /* 使用gets()讀取也可以，但因gets()未設讀入字元數的限制，可能導致儲存輸入字元的陣列空間爆掉 */
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if (line[0]=='\n') break; /* 輸入空字串則跳離此迴圈 */
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if (strstr(line,"{")) { /* line含有"{" */
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sscanf(line,"w = {%[^}]}",line);
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/* printf("大括弧內字串 %s\n",line); */
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rest = line;
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while (token = strtok_r(rest,s,&rest)) { /* strtok_r()的用法可參見 http://bit.ly/3VcvbbZ */
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/* printf("%s\n",token); */
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if (strstr(token,":")) {/* token含有":" */
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sscanf(token,"%[^:]:%d",key,&value);
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printf("Token #%d: 鍵=%s; 值=%d\n",++i,key,value);
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}
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}
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}
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else if (strstr(line,"del")) { /* line含有"del" */
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sscanf(line,"del w[%[^]]]",key);
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printf("刪除運算：鍵=%s\n",key);
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}
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else if (strstr(line,"+=")) { /* line含有"+=" */
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sscanf(line,"w[%[^]]] +=%d",key,&value);
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printf("遞增運算：鍵=%s；運算元=%d\n",key,value);
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}
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else if (strstr(line,"=")) { /* line含有"=" */
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sscanf(line,"w[%[^]]] = %d",key,&value);
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printf("指派運算：鍵=%s; 運算元=%d\n",key,value);
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}
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else if (sscanf(line,"w[%[^]]]?",key)==1)
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printf("讀值運算：鍵=%s\n",key);
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else if (strstr(line,"?"))
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printf("顯示整個字典內容(請同學實作，此為作業的一部分)\n");
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else
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printf("語法無法辨認，sorry!\n");
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}
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printf("\n程式結束，bye ~\n");
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return 0;
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}
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