Microsoft Word - CPMidTerm2011SpringSolution

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1 通識計算機程式設計期中考參考解答, 4/22/ (a) 宣告 int 變數 k, bool 變數 b, double 變數 x (3%) 答 : int k; bool b; double x; (b) 在螢幕顯示一行字, 要求使用者輸入一個整數 (3%) 答 : Console.WriteLine(" 輸入一個整數 "); (c) 自鍵盤讀入一個整數., 並將其值存入已宣告之 int 變數 k (3%) 答 : k = int.parse(console.readline()); 或 k = Convert.ToInt16(Console.ReadLine()); (d) 令已宣告之 bool 變數 b 等於邏輯敘述 : k 被 2 除之餘數等於 0 (3%) 答 : b = (k % 2 == 0); (e) 若.b 為真, 在螢幕顯示偶數否則印出奇數 (3%) 答 :if (b) Console.WriteLine(" 偶數 "); else Console.WriteLine(" 奇數 "); 或 string message = b? " 偶數 " : " 奇數 "; Console.WriteLine(message); 2. (a) 只用一個敘述, 將已宣告設值之 int 變數 n 以遞減算子減 1 後, 再設值 (assign) 給他處已宣告之 int 變數 m (3%) 答 : m = --n; (b) 宣告 bool 變數 r, 並設其值為 ( 非 p) 或 (or) q 之邏輯演算的結果 1/14

2 bool 變數 P 與 q 均已於他處已宣告設值 (3%) 答 : r =!p q; (c) 宣告 double 變數 y, 並令其值為他處已宣告設值之 double 變數 t 與 2 之積的餘弦函數 (cosine) 值, 注意此處為圓周率 (3%) 答 : double y = Math.Cos(2.0 * Math.PI * t); (d) 宣告 string 變數 state, 利用三元運算子使其在他處已宣告設值之 double 變數 membranepotential 大於等於 -55 時等於激發, 反之則等於靜態 (3%) 答 : string state = (membranepotential >= -55)? " 激發 " : " 靜態 "; (e) 宣告變數 c 為 char 型別, 並令其值為倒斜線 (back slash) 字元 (3%) 答 : char c = '\\'; 3. (a) 宣告一個 int 常數 N, 其值為 7 (3%) 答 : const int N = 7; (b) 宣告一個列數與行數均為為 N 的 int 二維陣列, 命名為 a (3%) 答 : int[,] a = new int[n, N]; (c) 宣告一個亂數產生器物件 rand, 種子數為 777 (3%) 答 :Random rand = new Random(777); (d) 將每個 a 陣列元素設為一個由 rand 產生, 在 2( 含 ) 與 12( 含 ) 之間的亂數 (3%) 答 : int i; int j; for(i=0; i<n; ++i) for (j = 0; j < N; ++j) a[i, j] = rand.next() % ; 2/14

3 (e) 計算 a 陣列各列的總和, 存入一維 int 陣列 rowsum 的對應元素令 rowsum 已於他處宣告 (3%) 答 : for (i = 0; i < N; ++i) rowsum[i] = 0; for (j = 0; j < N; ++j) rowsum[i] += a[i, j]; 4.. (a) (3%) int 1stPlace = 1; 答 : 變數名稱不可以數字開始更正 : int FirstPlace = 1; (b) (3%) 以下程式片段應產生三種輸出之一 : char age = Console.ReadLine().ToCharArray()[0]; switch (age) case ' 少 ': Console.WriteLine(" 紅燭昏羅帳 "); case ' 壯 ': Console.WriteLine(" 斷雁叫西風 "); default: Console.WriteLine(" 鬢已星星也 "); 答 : case 及 default 結束時須加上 break 敘述更正 : char age = Console.ReadLine().ToCharArray()[0]; switch (age) case ' 少 ': Console.WriteLine(" 紅燭昏羅帳 "); break; case ' 壯 ': Console.WriteLine(" 斷雁叫西風 "); break; default: Console.WriteLine(" 鬢已星星也 "); break; 3/14

4 (c) (3%) int i; while( i <= 3 ) Console.WriteLine( i/(i-1) ); ++i; 答 : i = 1, i/(i-1) 會發生除以 0 的例外更正 ( 合理的其他更正方式亦可 ): int i = 1; while (i <= 3) ++i; Console.WriteLine(i / (i - 1)); (d) (3%) 以下程式片段執行後, 應出現如後畫面 : for( int i=0; i<3; ++i ) Console.WriteLine( 0 計程再累, 我也要堅持到底!, i++); 答 : 迴圈中控制變數 i 發生改變, 使用到的 i 值只有 0, 2 兩個, 使輸出為更正 : for (int i = 0; i < 3; ++i) Console.WriteLine( "0 計程再累, 我也要堅持到底!", i+1); 4/14

5 (e) (3%) 下列程式片段應定義兩個函式. static void f1(int x) Console.WriteLine( f1(0), x); static void f2(int x) Console.WriteLine( f2(0), x); 答 : 函式 f2 不應定義在函式 f1 的一對大括弧之間. 更正 : static void f1(int x) Console.WriteLine("f1(0)", x); static void f2(int x) Console.WriteLine("f2(0)", x); 5. 試寫出下列程式的輸出 (5%) using System; namespace MidTerm2011Problem5 class Program static void Main(string[] args) int[] a = 4, 5, 6 ; int[] b = a; WhatDoesThisDo(a); Console.WriteLine("a[2] = 0, b[2] = 1", a[2], b[2]); 5/14

6 答 : static void WhatDoesThisDo(int[] x) x = new int[4] 8, 9, 0, 1 ; x[2] = 7; 6. 試寫出下列程式的輸出 (10%) using System; namespace MidTerm2011Problem6 class Program static void Main(string[] args) string pattern = "survey"; char[] p = pattern.tochararray(); string target = "surgery"; char[] t = target.tochararray(); int[,] c = DP(p, t); int n = t.length; int m = p.length; int i; int j; for (i = 0; i <= m; ++i) for (j = 0; j <= n; ++j) Console.Write(c[i, j] + "\t"); Console.WriteLine(); 6/14

7 static int[,] DP(char[] p, char[] t) int m = p.length; int n = t.length; int[,] c = new int[m+1, n+1]; int i; int j; for (j = 0; j <= n; ++j) c[0, j] = 0; for (i = 0; i <= m; ++i) c[i, 0] = i; for (i = 1; i <= m; ++i) for (j = 1; j <= n; ++j) c[i, j] = (p[i-1] == t[j-1])? c[i - 1, j - 1] : 1 + Minimum(c[i - 1, j], c[i, j - 1], c[i - 1, j - 1]); return c; static int Minimum(int x, int y, int z) if (x <= y && x <= z) return x; if (y <= x && y <= z) return y; return z; 7/14

答 : 7. /* * MidTerm2011Problem7 * skj, 4/21/2011 * 尋找英文文章中的 Semantic Words * 並計算其出現次數, 由高而低顯示 * * 主程式虛擬碼 * 1. 輸入文章中的文句, 以行為單位存成一維陣列 * 2. 假設儲存 semantic words 的陣列 * 是 semanticword * 對應的出現次數是陣列 freq * 3.

8 答 : 7. /* * MidTerm2011Problem7 * skj, 4/21/2011 * 尋找英文文章中的 Semantic Words * 並計算其出現次數, 由高而低顯示 * * 主程式虛擬碼 * 1. 輸入文章中的文句, 以行為單位存成一維陣列 * 2. 假設儲存 semantic words 的陣列 * 是 semanticword * 對應的出現次數是陣列 freq * 3. 取得 semanticword, freq * 4. 將 semanticword 及 freq 依 freq 由高而低排序 * 5. 輸出 semanticword 及 freq * * 函式虛擬碼 ProcessArticle( 文章, semanticword, freq) * 1. 假定放入 semanticword 及 freq 的單字數為 nsw * 令其初值為 0 * 2. for 文章每一行文句 * * 2.1 取出單字構成陣列 word * 2.2 for 所有 word 中的單字 * * if 單字是 stop words, continue * if 單字不在 semanticword 中 * * 將單字新增入 semanticword * 遞增 nsw 8/14

9 * * 遞增對應的 freq 元素 * * * * 測試規劃 : Robert Frost 的詩 The Road Not Taken 之最後一段 : * * I shall be telling this with a sigh * Somewhere ages and ages hence: * Two roads diverged in a wood, and I * I took the one less traveled by, * And that has made all the difference * * 應輸出 ( 括弧內代表出現次數, 由高而低排列, * 同次數單字出現序未必與此處相同 ): * ages (2) * telling (1) * sigh (1) * roads (1) * diverged (1) * wood (1) * less (1) * traveled (1) * difference (1) */ using System; using System.Diagnostics; namespace MidTerm2011Problem7 class Program static void Main(string[] args) Debug.Assert(Test_1_OK()); string[] semanticword; 9/14

10 int[] freq; int isw; string[] line = InputArticle(); ProcessArticle(line, out semanticword, out freq); Array.Sort(freq, semanticword); Array.Reverse(semanticWord); Array.Reverse(freq); Console.WriteLine( "\n 上列文章的 Semantic words 及出現次數 "); for (isw = 0; isw < semanticword.length; ++isw) Console.WriteLine("0 (1)", semanticword[isw], freq[isw]); static bool Test_1_OK() string[] semanticword; int[] freq; string[] line = new string[5] "I shall be telling this with a sigh", "Somewhere ages and ages hence:", "Two roads diverged in a wood, and I-", "I took the one less traveled by,", "And that has made all the difference" ; ProcessArticle(line, out semanticword, out freq); string[] correctsw = "ages", "telling", "sigh", "roads", "diverged", "wood", "less", "traveled", "difference" ; int[] correctfreq = 2, 1, 1, 1, 1, 1, 1, 1, 1 ; int isw; int idx; bool result = (semanticword.length == 9 && freq.length == 9); 10/14

11 if (result) for (isw = 0; isw < semanticword.length; ++isw) idx = Array.IndexOf( semanticword, correctsw[isw]); result = result && (idx >= 0 && freq[idx] == correctfreq[isw]); return result; static void ProcessArticle( string[] line, out string[] semanticword, out int[] freq) const int MAX_N_SW = 100; // 假設之 semantic words 字數上限 string[] sw = new string[max_n_sw]; // semantic words // 的 local 暫時版本 int[] fr = new int[max_n_sw]; // freq 的 local 暫時版本 int isw; for (isw = 0; isw < MAX_N_SW; ++isw) sw[isw] = null; fr[isw] = 0; int nlines = line.length; int il; string[] word; int nw; int iw; 11/14

12 int nsw = 0; for (il = 0; il < nlines; ++il) word = ProcessLine(line[iL]); nw = word.length; for (iw = 0; iw < nw; ++iw) if (IsAStopWord(word[iW])) continue; isw = Array.IndexOf(sw, word[iw]); if (isw < 0) isw = nsw; sw[isw] = word[iw]; ++nsw; fr[isw]++; // 產生要回傳的版本 semanticword = new string[nsw]; freq = new int[nsw]; Array.Copy(sw, semanticword, nsw); Array.Copy(fr, freq, nsw); static string[] InputArticle() Console.Write(" 輸入行數 : "); int nlines = int.parse(console.readline()); string[] line = new string[nlines]; int il; for (il = 0; il < nlines; ++il) Console.WriteLine(" 輸入第 0 行 ", il+1); line[il] = Console.ReadLine(); return line; 12/14

13 static string[] ProcessLine(string line) char[] separator = ' ', ',', '.', ':', ';', '\'','\\', '"', '/', '`', '-', ' ', '(', ')', '[', ']', '', '', '!', '@', '#', '$', '%', '^', '&', '*', '+', '_', '=', '~', '<', '>', '?' ; string[] word = line.split(separator); // 將單字改為全小寫, 以便比對 stop words int iw; for (iw = 0; iw < word.length; ++iw) word[iw] = word[iw].tolower(); return word; static bool IsAStopWord(string word) // 不算完全, 但可接受的 stop words 列表 string[] stopword = "","a","able","about","across", "after","all","almost","also","am", "among","an","and","any","are", "as","at","be","because","been", "but","by","can","cannot","could", "dear","did","do","does","either", "else","ever","every","for","from", "get","gets", "got","had","has", "have","he","hence","her","hers", 13/14

14 "him","his","how","however","i", "if","in","into","is","it", "its","just","least","let","lets", "likely","made","make", "makes", "may", "me","might","most","must","my", "neither","no","nor","not","of", "off","often","on","one","only", "or","other","our","own","rather", "said","say","says","shall","she", "should","since","so","some","somewhere", "take","taken","takes","than","that", "the","their","them","then","there", "these","they","this","tis","to", "too","took", "twas","two","us", "want","wants","was","we","were", "what","when","where","which","while", "who","whom","why","will","with", "would","yet","you","your" ; bool result = ( Array.IndexOf(stopword, word) >= 0 ); return result; 14/14

Microsoft Word - CPMidTerm2011Spring

Microsoft Word - CPMidTerm2011Spring 通識計算機程式設計期中考試題, 4/22/2011 共 8 頁, 滿分 100 分 1. 撰寫一或數個 C# 敘述達成下列要求 : ( 假設 using System; 敘述已經包含於程式中 ) (a) 宣告 int 變數 k, bool 變數 b, double 變數 x (3%) (b) 在螢幕顯示一行字, 要求使用者輸入一個整數 (3%) (c) 自鍵盤讀入一個整數., 並將其值存入已宣告之