判断每个字母在string中出现的次数

写了一个c++程序判断每个字母在string中出现的次数 但为什么无论输入什么，全部字母都显示出现0次？

#include 
#include 
using namespace std;
int count(const char * const s)
{
int count = new int[26];
for (int i = 0; i < 26; i++)
count[i] = 0;
for (int j = 0; j < strlen(s); j++)
{
    count[s[j] - 'a']++;
}

return count;
}
int main()
{
char str[100]; //100 is big enough to contain the string
cin >> str[100];
int* p = count(str);
for (int a = 'a'; a <= 'z'; a++)
{
cout << (char)(a) << ": " << p[a - 'a'] << " times" << endl;
} 
return 0;
}