作业5 四则运算 测试与封装 5.1
package sizeyunsuan; import java.util.Scanner; public class SortObject { private static int intercePosition = 0; // 记录单个运算数据的长度 private static int[] intercePositionIndex = null; // 记录“(”的下标 private static int[] intercePositionEnd = null; // 记录“)”的下标
public static void main(String[] args) { Scanner input = new Scanner(System.in); do { System.out.println("请输入你要计算的字符串(注意:只能输入数字和加,减,乘除符号;输入完毕后,请直接回车):"); String numberString = input.next().trim(); // 判断输入的运算字符串是否符合规定 if (ispassString(numberString) == false) { System.out.println("您输入的计算字符串有误,请正确输入!"); } else { // 计算结果返回 System.out.println(interceResult(numberString)); } } while (true); } // 判断是否有带括号的运算字符串存在 private static String interceResult(String str) { String result = str; char[] numberString = str.toCharArray(); // 1+2+(1*2+1-1*2+5)+2+(1+5+9+10-11)+1*5/2+3 // 1+8-9+(1*8/2-5+(1+2+8))+4/5*8/3*2 int IndexStart = 0; // 记录“(”的实际数量 int EndStart = 0; // 记录“)”的实际数量 for (int i = 0; i < numberString.length; i++) { if ('(' == numberString[i]) { // 记录最后一个正括号的位置 IndexStart = i; } if (')' == numberString[i]) { // 记录反括号的最初始下标的位置 EndStart = i; // 截取最里面一个括号里的运算字符串 result = result.substring(IndexStart + 1, EndStart); // 截取括号的运算字符串进行运算,生成新的运算字符串 result = str.substring(0, IndexStart) + interceptOperation(result, '*', '/') + str.substring(EndStart + 1, str.length()); // 回调执行,其它小括号的运算字符串 return interceResult(result); } if (i == numberString.length - 1) if (EndStart == 0) break; } // 不存在括号了,再进行混合运算 result = interceptOperation(str, '*', '/'); return result; }
// 不带括号的四则运算 private static String interceptOperation(String operationNumber, char a, char b) { String mess = operationNumber; char[] stringOperation = mess.toCharArray(); // 循环遍历运算字符串,并做相应的运算 for (int i = 0; i < stringOperation.length; i++) { // 判断运算符所在的索引 if (stringOperation[i] == a || stringOperation[i] == b) { if (i != 0) { // 运算符前的第一个数 double num1 = interceptNumIndex(mess.substring(0, i)); // 记录第一个数据的长度 int frontPosition = intercePosition; // 运算符前的第二个数 double num2 = interceptNumEnd(mess.substring(i + 1, stringOperation.length)); // 记录第二个数据的长度 int backPosition = intercePosition; // 算完乘除,将结果替换到原来运算的位置,得到新的运算字符串 String IndexMess = mess.substring(0, i - frontPosition + 1); String IndexResult = ""; // 判断是否运算到最后的结果了 if (IndexMess.indexOf('+') == -1 && IndexMess.indexOf('*') == -1 && IndexMess.indexOf('/') == -1 && IndexMess.lastIndexOf('-') == -1) IndexMess = ""; if (IndexMess != "") IndexResult = IndexMess.lastIndexOf('-') == IndexMess .length() - 1 ? IndexMess.substring(0, i - frontPosition) : IndexMess; // 组装新的运算字符串 mess = IndexResult// mess.substring(0,i-frontPosition+1) + reslutString("" + stringOperation[i], num1, num2) + mess.substring(i + backPosition + 1); // 0.111/1212/2/2/2/2/2/2/2 if (mess.lastIndexOf('-') == 0 && mess.indexOf('+') == -1 && mess.indexOf('*') == -1 && mess.indexOf('/') == -1) { break; } // 回调,继续运算 return interceptOperation(mess, a, b);// 1+7-5+89/3+4-6*8/2+4-6 } else continue; } if (i == stringOperation.length - 1) { // 递归出口,判断是否还有运算字符串在 if (mess.indexOf('+') != -1 || mess.indexOf('-') != -1) return interceptOperation(mess, '+', '-'); break; } } return mess; }
// 截取第二个数 private static double interceptNumEnd(String str) { double a = 0; int InrerceIndex = 0; char[] stringOperation = str.toCharArray(); boolean ispas = false; // 记录是否为负数 for (int i = 0; i < stringOperation.length; i++) { switch (stringOperation[i]) { case '*': case '/': case '+': case '-': InrerceIndex = i; if (i != 0) // 判断该数是否为负数 ispas = true; break; default: break; } if (ispas) break; } // 判断此数据是否在运算字符串的最后一位 if (InrerceIndex == 0) { a = Double.parseDouble(str); intercePosition = str.length(); if (ispas) intercePosition++; } else { a = Double.parseDouble(str.substring(0, InrerceIndex)); // 记录数据的真实长度 intercePosition = str.substring(0, InrerceIndex).length(); } return a; }
// 截取第一个数 private static double interceptNumIndex(String str) { double a = 0; // 记录数据 int InrerceIndex = 0; // 记录运算符的位置 boolean temp = false; // 记录数据前运算符的状态 char[] stringOperation = str.toCharArray(); for (int i = stringOperation.length - 1; i >= 0; i--) { switch (stringOperation[i]) { case '*': case '/': case '+': case '-': InrerceIndex = i; temp = true; break; default: break; } if (temp) break; } // 判断此数据是否在运算字符串的第一位 if (InrerceIndex == 0) { a = Double.parseDouble(str); intercePosition = str.length(); // if(temp) // intercePosition++; } else { a = Double.parseDouble(str.substring(InrerceIndex, str.length())); // 记录数据的真实长度 intercePosition = str.substring(InrerceIndex, str.length()) .length(); } return a; }
// 计算结果 private static double reslutString(String operation, double num1, double num2) { double sumResult = 0; if (operation.equals("*")) sumResult = num1 * num2; if (operation.equals("-")) sumResult = num1 - num2; if (operation.equals("/")) sumResult = num1 / num2; if (operation.equals("+")) sumResult = num1 + num2; return sumResult; }
// 判断是否正确输入运算方式 private static boolean ispassString(String messString) { boolean ispass = false; boolean operationIspass = true; // 记录被除数的状态 int ai = 0; // 记录是否有运算符号的存在 char[] IsString = messString.toCharArray(); int num1 = 0; int num2 = 0; for (int i = 0; i < IsString.length; i++) { // 记录有几对小括号的存在 if ('(' == IsString[i]) num1++; if (')' == IsString[i]) num2++; // 判断除数是否为零 if ('/' == IsString[i] && IsString[i + 1] == '0') operationIspass = false; // 判断是否输入了运算符合 if (IsString[i] == '+' || IsString[i] == '-' || IsString[i] == '*' || IsString[i] == '/') ai++; if (i == IsString.length - 1) if (ai == 0) num2++; } if (operationIspass) if (num1 == num2) ispass = true; return ispass; } }
因为之前做的是C++ ,这次重新做了java,改进上次的作业,看了助教eclipse的调试方法,因为我的软件是英文版,很多地方都看不明白,测试出来都是fail。
测试结果:
package sizeyunsuan; public class YunSuan { int ranswer=0; public int project1(char op,int a,int b){ switch(op) { case '+': ranswer=a+b;break; case '-': ranswer=a-b;break; case '*': ranswer=a*b;break; case '/': ranswer=a/b;break; } return ranswer; } public int project1(int c){ int jc=1; for(int i=c;i>0;i--) { jc=jc*i; } ranswer=jc; return ranswer; } }
package sizeyunsuan; import static org.junit.Assert.*; import org.junit.Test; public class YunSuanTest { @Test public void testProject1Int() { YunSuan core=new YunSuan(); int a=core.project1('+',3,7); assertEquals(10,a); } @Test public void testProject2Int() { YunSuan core=new YunSuan(); int a=core.project1('-',3,7); assertEquals(-4,a); } @Test public void testProject3Int() { YunSuan core=new YunSuan(); int a=core.project1('*',3,7); assertEquals(21,a); } @Test public void testProject4Int() { YunSuan core=new YunSuan(); int a=core.project1('/',8,2); assertEquals(4,a); } @Test public void testProject5Int() { YunSuan core=new YunSuan(); int a=core.project1('/',8,0); assertEquals(0,a); } }