Elimde bir örnek varmış. Yeterli olur sanırım.

#include "stdio.h"
#include "conio.h"
int sayi,onussu(int y);
void sayioku(),parcala(int x),degeryaz(int z),onlukyaz(int z);

main()
{
sayioku();
parcala(sayi);
getch();}

void parcala(int x)
{int us,bs;
for (us=5;us>=0;us--)
{ bs=x/onussu(us);
if(us!=4 && us!=1)
{if((us==5 || us==2)&& bs!=1)
degeryaz(bs);
switch(us)
{case 2: printf("yuz");break;
case 3: printf("bin");break;
case 5: printf("yuz");break;}}
else
onlukyaz(bs);

x=x%onussu(us);
}}
void sayioku()
{ printf("sayi giriniz\n");
scanf("%d",&sayi);
}
void degeryaz(int z)
{switch(z)
{case 1: printf("bir");break;
case 2: printf("iki");break;
case 3: printf("uc");break;
case 4: printf("dort");break;
case 5: printf("bes");break;
case 6: printf("alti");break;
case 7: printf("yedi");break;
case 8: printf("sekiz");break;
case 9: printf("dokuz");break;
}
}

void onlukyaz(int z)
{switch(z)
{case 1: printf("on");break;
case 2: printf("yirmi");break;
case 3: printf("otuz");break;
case 4: printf("kirk");break;
case 5: printf("elli");break;
case 6: printf("altmis");break;
case 7: printf("yetmis");break;
case 8: printf("seksen");break;
case 9: printf("doksan");break;
}
}


int onussu(int y)
{int i,s=1;
for(i=y;i>=1;i--)
s=s*10;
return s;}