// 10092009.cpp, P H Anderson, Oct 9, '09

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void cut_string(char *s, char *s1, char *s2, int num);  
    // num chars to s1, balance to s2
void alpha_string(char s[]);  // remove all non-numeric
int is_alpha(char ch);
int length_string(char *s);

#define TRUE !0
#define FALSE 0

int main()
{
    char sa[80] = {"Now is the time"}, sb[80], sc[80];
    
    printf("%s\n", sa);
    
    strcpy(sa, "Hello in MSU land");
    printf("%s\n", sa);
    cut_string(sa, sb, sc, 4);
    printf("After:  %s \n %s  \n", sb, sc);
    
    printf("Enter a string:");
    scanf("%s", sa);  // or scanf "%s", &sa[0]
    alpha_string(sa);
    printf("\n%s\n", sa);
    
    system("pause");
}

void cut_string(char s[], char s1[], 
                char s2[], int num)  
                // num chars to s1, balance to s2
{
    int len, n;
    len = length_string(s);
    if (num >= len)
    {
       strcpy(s1, s);
       strcpy(s2, "");
    }
    else
    {
        for (n=0; n<num; n++) 
        {
            s1[n] = s[n];
        }
        s1[num] = '\0';
        
        for (n=0; n < (len - num); n++)
        {
            s2[n] = s[num+n];
        }
        s2[n] = '\0';
    }
}                                                           

void alpha_string(char s[])  
{ // remove all non-numeric
    int len, m, n;
    len = length_string(s);    
    for (m=0, n=0; n<len; n++)
    {
        if (is_alpha(s[n]))
        {
            s[m] = s[n];
            ++m;
            
        }
    }
    s[m] = '\0';
}

int is_alpha(char ch)
{
    if ((ch >='a') && (ch <='z'))
    {
        return(TRUE);
    }
    else if ((ch >= 'A') && (ch <= 'Z'))
    {
        return(TRUE);
    }
    else
    {
        return(FALSE);
    }
}

int length_string(char *s)
{
    for(int n=0; n<80; n++)
    {
        if (s[n] == '\0')
        {
            return(n);
        }
    }
    return(80);  // trouble ?
}

#ifdef OUTPUT
Now is the time
Hello in MSU land
After:  Hell
 o in MSU land
Enter a string:The45^ghytre.
Theghytre
Press any key to continue . . .
#endif