#include<fstream> #include<string> using namespace std; int main() {     ifstream f("cifra.in");     ofstream g("cifra.out");     int t;     f>>t;     string numar;     int count=1;       int ultima_cifra[100];       int i=0;     int ucf=0;     while(i<=99)     {         int cifra=i%10;         switch(cifra)         {         case 2:             if(i%4==0)             {                 ucf=(ucf+6)%10;}             else if(i%4==1)             {                 ucf=(ucf+2)%10;             }             else if(i%4==2)             {                 ucf=(ucf+4)%10;             }             else            {                 ucf=(ucf+8)%10;             }             break;         case 3:             if(i%4==0)             {                 ucf=(ucf+1)%10;}             else if(i%4==1)             {                 ucf=(ucf+3)%10;             }             else if(i%4==2)             {                 ucf=(ucf+9)%10;             }             else            {                 ucf=(ucf+7)%10;             }             break;         case 4:             if(i%2==0)             {                 ucf=(ucf+6)%10;}             else            {                 ucf=(ucf+4)%10;}             break;           case 0: case 1: case 5: case 6:             ucf=(ucf+cifra)%10;             break;           case 7:             if(i%4==0)             {                 ucf=(ucf+1)%10;}             else if(i%4==1)             {                 ucf=(ucf+7)%10;             }             else if(i%4==2)             {                 ucf=(ucf+9)%10;             }             else            {                 ucf=(ucf+3)%10;             }             break;             case 8:             if(i%4==0)             {                 ucf=(ucf+6)%10;}             else if(i%4==1)             {                 ucf=(ucf+8)%10;             }             else if(i%4==2)             {                 ucf=(ucf+4)%10;             }             else            {                 ucf=(ucf+2)%10;             }             break;           case 9:               if(i%2==0)             {                 ucf=(ucf+1)%10;}             else            {                 ucf=(ucf+9)%10;}         }           ultima_cifra[i] = ucf;           i++;     }           while(count<=t)     {         f>>numar;         int i=1;         int ucf=0;           int cf;                   if(numar.length()>1)             cf = (numar[numar.length()-1]-'0')+(numar[numar.length()-2]-'0')*10;         else            cf = (numar[numar.length()-1]-'0');           g<<ultima_cifra[cf]<<endl;         count++;     } } 
.