标题：课上练习代码——统计字符串出现次数的函数

int main()
{
    char str1[100]="This is a revised version.";
    char str2[100]="is";
    printf("str2在str1中出现次数为%d次",countstr(str1,str2));

}

int countstr(char s1[],char s2[])
{
    int i=0,j=0,prei=0,count=0;;
    for(i=0; i<strlen(s1); i++)
    {
        prei=i;
        for(j=0; j<strlen(s2); j++)
        {
            if(s1[i]!=s2[j])
                break;
            else
                i++;
        }
        if(j>=strlen(s2))
            count++;
        i=prei;
    }
    return count;
}