Code Tìm Vị Trí số May mắn

//Code tim vi tri so may man //Thuat toan Bac Dang Sieu //Code by me //De /* Lucky Numbers* Lucky Numbers are only numbers 4 or 7 EX: 4, 7, 44, 47, 74, 77,... Question: Find location of Lucky number Ex: Input: 447 Output: 8 */ #include<stdio.h> #include<math.h> //Ham dem chu so cua so n int countLN(int n) { int count=0, temp; while (n>0) { n/=10; count++; } return count; } //ham kiem tra so n co phai so may man hay khong? bool checkLN(int n) { bool check = true; int temp; while (n>0) { temp = n%10; if (temp!=7 && temp!=4) { check = false; break; } n/=10; } return check; } int main() { long n; int temp, i, location=0; //control so may man n do{ printf("Input your Lucky Number: "); scanf("%ld",&n); if (checkLN(n)==false) { printf("\nSo ban vua nhap khong phai so may man, moi ban nhap lai!\n"); } } while(checkLN(n)==false); int count = countLN(n); int a[count]; //dua tung chu so cua n vao mang if(checkLN(n)==true) { for (i=count-1;i>=0;i--) { a[i]=n%10; n/=10; } } //di den vi tri dau tien cua so //Vi du 444 co 3 chu so se //la 1+2+2^n-1 se la 1+2+3=7 for(i=1;i<=count;i++) { location+=pow(double(2),i-1); } //tim vi tri so may man do for (i=0;i<count;i++) { if (a[i]>4) { location+=pow(double(2),count-i-1); } } printf("\nSo may man ban vua nhap o vi tri thu: %d",location); return 0; }