C++实现：

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

/**
 * 字符串
 */
bool findMostFrequentString(string* a, int size, string &val)
{
    if (size <= 0)
        return false;
    
    map<string, int> m;
    for (int i = 0; i < size; i++)
    {
        m[a[i]]++;
        if (m[a[i]] > m[val])
            val = a[i];
        //cout << a[i]<<m[a[i]] << endl;
    }
    return true;
}

int main(int argc, const char * argv[]) {
    
    string val = "z";
    string a[] = { "apple", "apple", "banana", "banana", "banana"};
    if (findMostFrequentString(a, 5, val))
        cout << val << endl;
    getchar();
    return 0;
}