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

    // strlen strdup strcpy strncpy strcat

#define T printf("%s body='%s'\n", __PRETTY_FUNCTION__, body)

class str {
public:
    str(const char *val = "") {
        body = strdup(val);
        T;
    }

    ~str() {
        T;
        free(body);
    }

    void print() const {
        printf("[%s]\n", body);
    }

    str & operator= (const str &b) {
        free(body);
        body = strdup(b.body);
        T;
        return *this;
    }

    str(const str &b) {
        body = strdup(b.body);
        T;
    }

    str operator+ (const str &b) const {
        T;
        size_t need = strlen(body) + strlen(b.body) + 1;
        str ret("");
        ret.body = (char *)realloc(ret.body, need);
        assert(ret.body != nullptr); 
        strcpy(ret.body, body);
        strcat(ret.body, b.body);
        return ret;
    }
private:
    char *body;         // C-string, null-terminated "123" -> '1', '2', '3', 0
};

void foo(str c) {
    printf("foo!");
    c.print();
}

int main() {
    str a("abra");
    str b("shvabra");
    str c = a + b;
    str e(a+b);
    a.print();
    b.print();
    c.print();
    c = a;
    c.print();
    str d = a;
    d.print();
    // str c = a + b;
}