#include <stdio.h>
int main()
{
    void copy_string(char *from,char *to);
    char *a="I am a teacher";
    char *b="you are a student";
    printf("sting a is:%s\nstring b is :%s\n",a,b);
    copy_string(a,b);
    printf("%s,%s",a,b);
}

void copy_string(char *from,char *to)
{
    for (;*from!='\0';from++,to++)
    {
        *to=*from;
    }
    *to='\0';
}