模拟小数幂
小数点位 pos
非零末位 e
长度 len
只有三种情况
pos > len
pos < e
e < pos < len
1 #include <iostream> 2 #include <cstring> 3 using namespace std; 4 int a[500], b[500], c[500]; 5 void Cal() 6 { 7 memset(c, 0, sizeof(c)); 8 for(int i = 0; i < 200; i++) 9 for(int j = 0; j < 10; j++) 10 c[i+j] += a[i] * b[j]; 11 for (int i = 0; i < 200; i++){ 12 c[i+1] += c[i]/10; 13 c[i] %= 10; 14 } 15 memset(a, 0, sizeof(a)); 16 for (int i = 0; i <= 200; i++) 17 a[i] = c[i]; 18 } 19 char s[10]; 20 int pos, n, len; 21 int main() 22 { 23 while(cin>>s>>n) 24 { 25 memset(a,0,sizeof(a)); 26 memset(b,0,sizeof(b)); 27 memset(c,0,sizeof(c)); 28 int t = 0; 29 for (int i = 5; i >= 0; i--) 30 { 31 if(s[i]=='.') pos = i; 32 else b[t++] = s[i] - '0'; 33 } 34 a[0] = 1; 35 for(int i = 1; i <= n; i++) Cal(); 36 len = 200; 37 while(!c[len] && len>=0) len--; 38 int e = 0;//末尾 39 while(!c[e] && e<= len) e++; 40 pos = 5 - pos; pos *= n;//小数点 41 if(pos > len) 42 { 43 cout<<"."; 44 for (int i = pos-1; i >= e; i--) cout<<c[i]; 45 cout<<endl; 46 } 47 else if(pos <= e)//整数 48 { 49 for (int i = len; i >= pos; i--) cout<<c[i]; 50 cout<<endl; 51 } 52 else//普通 53 { 54 for (int i = len; i >= pos; i--) cout<<c[i]; 55 cout<<"."; 56 for (int i = pos-1; i >= e; i--) cout<<c[i]; 57 cout<<endl; 58 } 59 } 60 }