#include
#include
void func(char *s1,char *s2)
{
char *p1 = s1;
char *p2 = s2;
int n1 = strlen(s1);
int i = n1 ;
int j = 0;
do{
p1[i] = p2[j];
i++;
j++;
}while(p2[j] != '\0');
}
int main(void)
{
char s1[20]={'a','b','c','\0'};//<------------
char s2[] = {'d','e','f','\0'};//<------------
func(s1,s2);
printf("%s\n",s1);
return 0;
}