Question

Why is the following program stuck in a following loop after “Done!”, and then ends with a crash?

#include <iostream>
using namespace std;
#include <cstring>

struct stringy{
    char * str;
    int ct;
};

void set(stringy & s, const char * cs);
void show(const char * s, int times=1);
void show(const stringy & s, int times=1);

int main(){
    stringy beany;
    char testing[] = "Reality isn't what it is used to be.";
    set(beany, testing);
    show(beany);
    show(beany, 2);
    testing[0] = 'D';
    testing[1] = 'u';

    show(testing);
    show(testing, 3);
    show("Done!");

    return 0;
}

void set(stringy & s, const char * cs){
    s.ct = strlen(cs);
    strcpy(s.str, cs);
}

void show(const char * s, int times){
    while (times-- > 0){
        cout << s << endl;
    }
}

void show(const stringy & s, int times){
    show(s.str, times);
}

Answer 1

Allocate memory for string before copying

void set(stringy & s, const char * cs){
    s.ct = strlen(cs);
    s.str = new char[s.ct+1];
    strcpy(s.str, cs);
}

Free the memory

delete[] beany.str;