0

hallo i wrote a program with 3 different functions.

something wrong with her and i cant see it.

```
#include<stdio.h>
int devide9(int num);
int decimal_binar(int num);
int binar_decimal(int num);
int main()
{
int menu, num9, numd1, numb1, numd2, numb2, numfinal1;
printf("\nHallo these are your options:\n");
printf("1. Check if your number can be devide by 9 without residue.\n");
printf("2. Decimal - binar converter.\n");
printf("3. Binar - decimal converter.\n");
printf("4. Exit.\n");
scanf("%i", &menu);
switch (menu)
{
case 1:
printf("please enter a number:\n");
scanf("%i", &num9);
numfinal1 = devide9(num9);
if (numfinal1 == 9)
printf("the number can be devided by 9.\n");
else
printf("the number can not be devided by 9.\n");
main();
case 2:
printf("please enter a number:\n");
scanf("%i", &numd1);
numb1 = decimal_binar (numd1);
if (numd1<0)
printf("%i (base 10) => -%i (base 2)\n", &numd1, &numb1);
else
printf("%i (base 10) => %i (base 2)\n", &numd1, &numb1);
main();
case 3:
printf("please enter a number:\n");
scanf("%i", &numb2);
numd1 = binar_decimal(numb2);
if (numd2<0)
printf("%i (base 2) => -%i (base 10)\n", &numb2, &numd2);
else
printf("%i (base 2) => %i (base 10)\n", &numb2, &numd2);
main();
case 4:
return(0);
break;
default: main(); break;
}
return(0);
}
int devide9 (int num)
{
int numT, num1;
if (num<0)
num = num*-1;
numT = 0;
while (num > 0 );
{
num1 = num%10;
numT = num1 + numT;
num = num/10;
}
if (numT>9)
numT = devide9 (numT);
return (numT);
}
int decimal_binar (int num)
{
int counter, multi, i, numT, num1, numd1;
if (num<=1023 && num >= -1023)
{
if (num<0)
num = num*-1;
counter = 0;
numT = 0;
while (num > 0 );
{
num1 = num % 2;
num = num / 2;
if (counter == 0)
numT = num1;
else
{
multi = 1;
for (i=1; i<=counter; i++)
{
multi = 10 * multi;
}
}
numT = multi * num1 + numT;
counter = counter +1;
}
}
else
{
printf("please enter a new number:\n");
scanf("%i", &numd1);
numT = decimal_binar(numd1);
}
return (numT);
}
int binar_decimal (int num)
{
int num1, counter, hez1, hezT, i,numT, numb1;
counter = 0;
if (num >= -1111111111 && num <= 1111111111)
{
if (num < 0)
num = num*-1;
counter = 0;
numT = 0;
while (num > 0 );
{
num1 = num % 10;
hez1 = hezT = 1;
for (i=1; i<=counter; i++)
{
hez1 = hezT;
hezT = hez1*2;
}
numT = num1*hezT + numT;
counter = counter + 1;
num = num / 10;
}
}
else
{
printf("please enter a new number:\n");
scanf("%i", &numb1);
numT = binar_decimal (numb1);
}
return (numT);
}
```