#include 
                      #include 
                      #include 
                      int main(){
                        int x,y,z,N,prod=1,i,n,a,sum=0,p=0,e;
                        long long  int bin=0;
                        bool continu=true;
                        
                        do{
                          
                        printf("enter base you will enter:");
                        scanf("%d",&x);
                        printf("enter base you want convert to:");
                        scanf("%d",&y);
                        
                        
                        
                        
                        switch(x){
                          
                          
                          
                          
                        case 10:
                          if(y==8){
                            printf("N=");
                            scanf("%d",&N);
                            printf("%o",N);
                        }
                          else if(y==16){
                              printf("N=");
                            scanf("%d",&N);
                            printf("%X",N);
                        }
                          else if(y==2){
                            printf("N=");
                            scanf("%d",&N);
                            a=N;
                              if(a<0){
                                    printf("Take care the number will read from down to up\n");
                                    printf("take care the combleat bits its one's\n");
                                  a=-1*a;
                                  ++a;
                                  for(;a>0;){
                                      i=a%2;
                                      a/=2;
                                      if(i==0)
                                            printf("1\n");
                                        else 
                                            printf("0\n");
                          }}
                              else{
                                a=N;
                                for(;a>0;){
                                        i=a%2;
                                        bin+=i*prod;
                                        prod*=10;
                                        a/=2;
                          }
                                    printf("%d",bin);
                        }	
                        }
                            break;
                        
                        
                        
                        
                        
                        case 8:
                            if(y==10){
                                printf("N=");
                                scanf("%o",&N);
                                printf("%d",N);
                        }
                            else if(y==16){
                                printf("N=");
                                scanf("%o",&N);
                                  printf("%X",N);
                        }
                            else if(y==2){
                              printf("Take care the number will read from down to up\n");
                              printf("N=");
                              scanf("%d",&N);
                              a=N;
                                  while(a!=0){
                                        i=a%10;
                                        a/=10;
                                        if(i==0){printf("000\n");}
                                        else if(i==1){printf("001\n");}
                                        else if(i==2){printf("010\n");}
                                        else if(i==3){printf("011\n");}
                                        else if(i==4){printf("100\n");}
                                        else if(i==5){printf("101\n");}
                                        else if(i==6){printf("110\n");}
                                        else if(i==7){printf("111\n");}
                                        else{
                                              printf("enter octal number!!!!");
                                              break;
                      }
                        }
                          
                      }
                              break;
                          
                        
                        
                        
                        case 16:
                                if(y==10){
                                    printf("write in lowercase\nN=");
                                    scanf("%x",&N);
                                    printf("=%d",N);
                        }
                              else if(y==8){
                                  printf("write in lowercase\nN=");
                                  scanf("%x",&N);
                                  printf("%o",N);
                        } 
                            else if(y==2){
                                printf("write in lowercase\nN=");
                                scanf("%x",&N);
                                printf("take care the number will read from down to up\n");
                                a=N;
                                for(;a>=1;){
                                      i=a%2;
                                      a/=2;
                                      printf("%d\n",i);
                          }
                          
                        }
                            break;
                        
                        
                        
                        
                        case 2:
                            printf("N=");
                            scanf("%d",&N);
                            a=N;
                            for(;a>0;){
                              i=a%10;
                              if(i==1||i==0){
                              sum+=i*pow(2,p++);
                              a/=10;
                              e=1;
                              }
                              else{
                                e=0;
                                break;
                              }
                            }
                            if(e==1){
                              if(y==16){
                                printf("%x",sum);
                          }
                              else if(y==10){
                                printf("%d",sum);
                          }
                              else if(y==8){
                                printf("%o",sum);
                          }}
                          else
                              printf("illegal number!!\nEnter BINARY number!");
                              
                              break;
                          
                          default:
                            printf("illegal number!!");
                          }
                          printf("\n");
                          
                        }while(continu);

                        return 0;
                      }