查找子字符串中字符的出现次数

Question

查找字符串子字符串中字符出现次数的最快方法是什么？

我尝试过正常扫描每个字符但测试数据太大。

Answer 1

这很简单

unsigned int countChar(const char *string, char characterOfInterest)
 {
    unsigned int count; 

    count = 0;
    while ((string = strchr(string, characterOfInterest)) != NULL)
     {
        count  += 1;
        string += 1;
     }
    return count;
 }