#include <stdio.h>
#include <math.h>
#include<string.h>
void number_system(int N)
{
  if(N==1){
int a[10],n,i;

printf("Desimal To Binary: ");
scanf("%d",&n);
for(i=0;n>0;i++)
{
a[i]=n%2;
n=n/2;
}
printf("\nBinary of Given Number is=");
for(i=i-1;i>=0;i--)
{
printf("%d",a[i]);
}
}
if(N==2){
        char h[15];
 int i=0,d,k;
 printf("Desimal To Hexadesimal:");
 scanf("%d",&d);
 while(d!=0)
 {
     k=d%16;
     if(k>9)
        h[i]=(char)(k+55);
     else
        h[i]=(char)(k+48);
     d=d/16;
     i++;
 }
 h[i]='\0';
 strrev(h);
 printf("%s",h);
}
if(N==3)
{
 int dec,oct=0,rem,k=1;
 printf("Desimal To Octal:");
 scanf("%d",&dec);
 while(dec!=0)
 {
     rem=dec%8;
     oct=rem*k+oct;
     k=k*10;
     dec=dec/8;
 }
 printf("%d",oct);
}
if(N==4)
{
      int dec=0,bin,base=1,rem,num;
  printf("Binary To Decimal:");
  scanf("%d",&bin);
  while(bin!=0)
  {
      rem=bin%10;
      dec=dec+rem*base;
      bin=bin/10;
      base=base*2;
  }
  printf("%d",dec);
}
if(N==5)
{
        long int bin, hex = 0, i = 1, rem;

    printf("Binary To Hexadesimale: ");
    scanf("%ld", &bin);
    while (bin != 0)
    {
        rem = bin % 10;
        hex = hex + rem * i;
        i = i * 2;
        bin = bin / 10;
    }
    printf("%lX", hex);
}
if(N==6)
{
      long int bin, oct = 0, j = 1, rem;

    printf("Binary To Octal: ");
    scanf("%ld", &bin);
    while (bin != 0)
    {
        rem = bin % 10;
        oct = oct + rem * j;
        j = j * 2;
        bin = bin / 10;
    }
    printf("%lo", oct);
}
if(N==7)
{
      char bin[1000], hex[1000];
    long int i = 0;

    printf("Hexadesimal To Binary: ");
    scanf("%s", hex);
    while (hex[i])
    {
        switch (hex[i])
        {
        case '0':
            printf("0000"); break;
        case '1':
            printf("0001"); break;
        case '2':
            printf("0010"); break;
        case '3':
            printf("0011"); break;
        case '4':
            printf("0100"); break;
        case '5':
            printf("0101"); break;
        case '6':
            printf("0110"); break;
        case '7':
            printf("0111"); break;
        case '8':
            printf("1000"); break;
        case '9':
            printf("1001"); break;
        case 'A':
            printf("1010"); break;
        case 'B':
            printf("1011"); break;
        case 'C':
            printf("1100"); break;
        case 'D':
            printf("1101"); break;
        case 'E':
            printf("1110"); break;
        case 'F':
            printf("1111"); break;
        case 'a':
            printf("1010"); break;
        case 'b':
            printf("1011"); break;
        case 'c':
            printf("1100"); break;
        case 'd':
            printf("1101"); break;
        case 'e':
            printf("1110"); break;
        case 'f':
            printf("1111"); break;
        default:
            printf(" %c ", hex[i]);
        }
        i++;
    }
}
if(N==8)
{
     int n;
  printf("Hexadesimal to octal: ");
  scanf("%x",&n);
  printf("%o", n);
}
if(N==9)
{

}
}
 int main()
 {
     int N;
     printf("Press any number(1 to 12):");
     scanf("%d",&N);
     number_system(N);
     return 0;
 }