Question

编程实现strcpy.strcat.strlen.用指针

Answer 1

char* strcpy(char* to, char* from)
{
char* p = to;
while(*to++ = *from++);
return p;
}
char* strcat(char* a, char* b)
{
char* p = a;
while(*a)++a;
while(*a++ = *b++);
return p;
}

int strlen(char* a)
{
int len = 0;
while(*a++)++len;
return len;
}