关于利用指针替换特定字符的问题

#include <iostream>
using namespace std;
int replace(char*str,char a,char c);
int main()
{
    char* str = "hhhhhhhhhaaaaaaaaacccccccc";
    char a = '*';
    char c = 'h';
    int count = replace(str,a,c);
    replace(str, a, c);
    cout << count << endl;
    cout << str << endl;
    return 0;
}
int replace(char* str, char a, char c)
{
    int count = 0;
    while (*str)
    {
        if (*str == c)
        {
            *str = a;
            count++;
        }           
        str++;
    }
    return count;
}

以上是我的代码，但是运行结果是一个不停闪烁的光标，啥也没有

char* str = "hhhhhhhhhaaaaaaaaacccccccc";
这是字符串常量，不能replace

#include <iostream>
using namespace std;
int replace(char*str,char a,char c);
int main()
{
    char str[] = "hhhhhhhhhaaaaaaaaacccccccc";
    char a = '*';
    char c = 'h';
    int count = replace(str,a,c);
    cout << count << endl;
    cout << str << endl;
    return 0;
}
int replace(char* str, char a, char c)
{
    int count = 0;
    while (*str)
    {
        if (*str == c)
        {
            *str = a;
            count++;
        }           
        str++;
    }
    return count;
}

9
*********aaaaaaaaacccccccc