Use an array to calculate the factorial of n (n is relatively large) and the number of 0 at the end

// Use an array to calculate the factorial of N (where N is relatively large) and the number of 0 at the end // convert from: struct <iostream> # include <vector> # include <algorithm> using namespace STD; string add (string num1, string num2) {// large addition string result = ""; int len1 = num1.length (); int len2 = num2.length (); int naddon = 0; // carry int I, j, N1, N2, sum; vector <char> tmpsum; for (I = len1-1, j = len2-1; I> = 0 & J> = 0; -- I, -- J) {n1 = num1 [I]-'0'; N2 = num2 [J]-'0'; sum = N1 + N2 + naddon; If (sum> = 10) naddon = 1; elsenaddon = 0; tmpsum. push_back (sum % 10 + '0');} If (len1> len2) {// The first one has the remaining for (; I> = 0; -- I) {n1 = num1 [I]-'0'; sum = N1 + naddon; If (sum> = 10) naddon = 1; elsenaddon = 0; tmpsum. push_back (sum % 10 + '0') ;}} else if (len2> len1) {// The second for (; j> = 0; -- J) {n2 = num2 [J]-'0'; sum = n2 + naddon; If (sum> = 10) naddon = 1; elsenaddon = 0; tmpsum. push_back (sum % 10 + '0');} If (naddon> 0) {tmpsum. push_back (naddon + '0');} // because the result is inverted, reverse (tmpsum. begin (), tmpsum. end (); copy (tmpsum. begin (), tmpsum. end (), back_inserter (result); return result;} string multipy (string num1, string num2) {// multiplication of large numbers, multiplication is essentially the addition of the accumulated string result = "0"; int I, j, N1, N2; int len1 = num1.length (); int len2 = num2.length (); if (len1 <len2) {for (I = len1-1; I> = 0; -- I) {n1 = num1 [I]-'0 '; string sum = "0"; for (j = 0; j <N1; ++ J) sum = add (sum, num2); string tmpsb (SUM ); for (j = I; j <len1-1; ++ J) tmpsb. append ("0"); Result = add (result, tmpsb) ;}} else {for (I = len2-1; I> = 0; -- I) {n2 = num2 [I]-'0'; string sum = "0"; for (j = 0; j <N2; ++ J) sum = add (sum, num1); string tmpsb (SUM); For (j = I; j <len2-1; ++ J) tmpsb. append ("0"); Result = add (result, tmpsb) ;}} return result;} string factorial (int n) {string result = "1 "; char buff [100]; for (INT I = N; I> = 2; -- I) {result = multipy (result, ITOA (I, buff, 10 ));} return result;} int countzero (string res) {char ch [100]; int COUNT = 0; int Len = res. length (); char * P = CH + len-1; strcpy (CH, Res. c_str (); While (* P = '0') {count ++; p --;} return count;} int func (int n) {If (n> 0 & n <5) return 0; else {int K = N/5; return K + func (k) ;}} int main () {int N; CIN> N; int count; string STR = factorial (n); cout <Str. c_str () <Endl; Count = countzero (STR); cout <count <Endl; cout <func (n) <Endl; return 0 ;}