izbaci substring - bez string.h

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


void izbaci(char* string, char* substring)
{
    while(*string != '\0')
    {
        char* sub = substring;
        char* str = string;
        while(*sub != '\0' && *str == *sub)
        {
            sub++;
            str++;
        }
        if(isalpha(*sub)==0)
        {
            while(*str != '\0')
            {
                *string++=*str++;
            }
            *string = '\0';
        }
        string++;
    }
}

int main()
{
    char s[]="izbaci ovuh test";
    izbaci(s, "ovu");
    puts(s);
    return 0;
}