PAT (Basic Level) Practice(1002)

#include<stdio.h>
#include<string.h>
int NumberCh(int a)
{
	switch(a)
	{
		case 0:
			printf("ling");
			break;
		case 1:
			printf("yi");
			break;
		case 2:
			printf("er");
			break;
		case 3:
			printf("san");
			break;
		case 4:
			printf("si");
			break;
		case 5:
			printf("wu");
			break;
		case 6:
			printf("liu");
			break;
		case 7:
			printf("qi");
			break;
		case 8:
			printf("ba");
			break;
		case 9:
			printf("jiu");
			break;
		default:
			printf("Data Error!");
			break;
			return 0;
	}
}
int main()
{
	char str[100];
	int sum=0,len,num[1005];
	int a[10],i,j=0;
	scanf("%s",str);
	len = strlen(str);
	for(i=0; i<len; i++)
	{
		num[i] = str[i]-'0';
		sum = sum+num[i];
	}
	if(sum==0)
	{
		NumberCh(0);
	}
	while(sum!=0)
	{
		a[j]=sum%10;
		sum=sum/10;
		j++;
	}
	for(int i=j-1; i>0; i--)
	{
		NumberCh(a[i]);
		printf(" ");
	}
	NumberCh(a[0]);
	return 0;
}