done

report.md

@@ -95,27 +95,19 @@ remove all nodes in the link list, construct new link list by copying the value
 
 ##### d. `a / b`: 
 
-1. if b equals to 0, throw division by zero error
-
-2. remove dot of absolute value of a and b, namely `a'` and `b'`.
-
-3. calculate the quota for decimal points in the quotient, which is max of precision of a and b +1 (for rounding)
-
-4. Evaluate max_d, which is the maximum number of zero can be appended to b' to make it just smaller than a'
-
-5. begin the recurrence relation:
-
-   1. a' > b' 
-      ​	no more quota $=>$ end with NULL
-      ​	have quota
-      ​		do a' * 10 /b and drop one quota, and if it is the first time to use quota, append .
-
-   2. else
-
-      ​	evaluate number of times a' can be subtracted  by ${b'}*10^{max_d}$ and let it be d.
-
-      ​	returned number is d coming with resultant digits of $(a'-d*{b'}*10^{max_d})/b'$ which this / sign 
-      ​	is calling the 	recurrence function with max_d decrease by 1.
+1. preprocess:
+   1. if b equals to 0, throw division by zero error
+   2. let absolute of `a` and `b` be `a'` and `b'` respectively.
+   3. calculate the resultant precision as 1+ max of a's precision and b's precision.
+   4. make a' to be $a' * 10^{precision}$ so that the quotient will have extra digits (calculating the decimals).
+2. recursion:
+   1. if a<b terminate 2. with 0
+   2. else 
+      1. calculate the more significant quotient, p, by calling a/(b*10)
+      2. calculate the remainder by the more significant quotient, $r=a' - b*p*10$ 
+      3. let the quotient generated by this recursion level is $q$, while $r>=b'$, subtract $b'$ from $r$ and $q$ increment by 1.
+      4. finally leave 2. with the combined quotient of this recursion level and previous levels, $q+p*10$
+   3. add back the sign and decimal point to the rounded result and return.
 
 ##### e. `a ^ b `:
 
@@ -124,8 +116,8 @@ remove all nodes in the link list, construct new link list by copying the value
 3. if b equals 1, result is a
 4. if b equals 2, result is a*a
 5. else 
-   1. turn $b$ to a bit-string, set result as 1.
-   2. for each digit $b_i$ in $b$, if $b_i$ is 1,result multiply by ${a}^{2^i}$ 
+   1. turn $b$ to a bit-string, set `result` as 1.
+   2. for each digit $b_i​$ in $b​$, if $b_i​$ is 1, `result` multiply by ${a}^{2^i}​$ 
    3. return result
 
 ##### f. increment and decrement

task1/bigDecimal.cpp

@@ -559,8 +559,6 @@ BigDecimal BigDecimal::operator/(const BigDecimal &bi) const{
     for(int i=0; i<quota; i++){
         a=a*10;
     }
-
-//    cout<<"quota "<<quota<<endl;
 
     BigDecimal result = div(a,b);
     result.linkList->data = (sign()==bi.sign()?'+':'-');