C ++字符串递归substr

Question

I am trying to compute recursively the number of times that sub appears inside str, without the substrings overlapping. What I am trying to do is str.find(sub) and if it exist count++ and then return the count + recalling the function but without the found position: str.substr(str.find(sub) + sub.length())

Here are some examples:
subCcount("catcowcat", "cat") returns 2 
subCount("catcowcat", "cow") returns 1 
subCount("catcowcat", "dog") returns 0

The code I tried writing:

int count = 0;   
int subCount(const std::string& str, const std::string& sub)
{
    int len = str.length();
    if(len == 0)
    {
        return 0;
    }
    else
    {
        if(str.find(sub) != string::npos)
        {
            count++;
            return count + subCount(str.substr(str.find(sub) + sub.length()), sub);
        }
    }
}

Testing the Code:

X subCount("catcowcat", "cat"): expected [2] but found [3]

X subCount("catcowcat", "cow"): expected [1] but found [3]

'+ subCount("catcowcat", "dog")

X subCount("cacatcowcat", "cat"): expected [2] but found [9]

Answer 1

You should definitely use a debugger and check for basic errors before asking for help.

• Initialize count to zero in the beginning of that function.
• Add an else statement returning count value for the if(str.find(sub) != string::npos).

I hope this solves your problem.