以下是引用片段: public class Calculator{ private String result = "0"; private int op = 0,add = 1,sub = 2,mul = 3,div = 4; private double stringToDouble(String x){ double y = Double.parseDouble(x); return y; } private void operate(String x){ double x1 = stringToDouble(x); double y = stringToDouble(result); switch (op){ case 0: result = x; break; case 1: result = String.valueOf(y+x1); break; case 2: result = String.valueOf(y-x1); break; case 3: result = String.valueOf(y*x1); break; case 4: if(x1!=0){ result = String.valueOf(y/x1); }else{ result = "The divisor can't be zero!"; } break; } } public String opAdd(String x){ operate(x); op = add; return result; } public String opSubtract(String x){ operate(x); op = sub; return result; } public String opMultiply(String x){ operate(x); op = mul; return result; } public String opDivide(String x){ operate(x); op = div; return result; } public String opEquals(String x){ operate(x); op = 0; return result; } public void opClean(){ op = 0; result = "0"; } } |