Code:
I think this would help you.
#include <stdio.h>
#include <ctype.h>
int main()
{
int num1;
printf("Insert a number from 0 to 9: ");
scanf("%d",&num1);
if(num1< 0 || num1>9)
printf("error\n");
else if ( num1==0)
printf("zero");
else if( num1==1)
printf("one");
else if( num1==2)
printf("two");
else if( num1==3)
printf("three");
else if( num1==4)
printf("four");
else if( num1==5)
printf("five");
else if( num1==6)
printf("six");
else if( num1==7)
printf("seven");
else if( num1==8)
printf("eight");
else
printf("nine");
return 0;
}