查找指定字符串在某个字符串中的出现次数

c语言代码实现：

#include<stdio.h>
#include<string.h>
int searchnum(char *str,char *pattern)
{
        if (str == NULL)
            return 0;
        char *pos = NULL;
        int count = 0;
        while ((pos = strstr(str,pattern)) != NULL)
        {
            count++;
            pos += (strlen(pattern));
            str = pos;
    //        count = count+1;
        }
        return count;
}
int main()
{
    char *str = "world hello world word world";
    printf("%d\n",searchnum(str,"world"));
    return 0;
}

运行结果：
[root@localhost ~]# ./a.out
3