/* Write a function changeString that has two parameters: 
two character arrays: old_array and new_array. 
The function changes the original array in the following way: 
each digit is replaced by the character '*', 
all chars that are not letters and digits are omitted, 
and the rest of the chars remain the same 
Write a program that reads original string, make changes and prints string after changes are made. For example:
Input: Yana123*((!
Output: Yana***  */

#include<stdio.h>
void changeString(char old_str[], char new_str[]);
#define SIZE 21

int main(){
	char old_str[SIZE], new_str[SIZE];
	printf("enter a string max 20 characters\n");
	scanf("%s",old_str);
	
	changeString(old_str, new_str);
	printf("new string is %s\n", new_str);
	return 0;
}
void changeString(char old_str[], char new_str[]){
	int i=0, j=0;
	while(old_str[i]!='\0'){
		if(old_str[i]>='0' && old_str[i]<='9'){
			new_str[j]='*';
			j++;
		}
		else if((old_str[i]>='a' && old_str[i]<='z')||(old_str[i]>='A' && old_str[i]<='Z')){
			new_str[j]=old_str[j];
			j++;
		}
		
		i++;
	}
	new_str[j]='\0';
}