c++课后作业

把字符串转换为整数

int main()
{
	char pn[21];
	cout > pn;
	int last = 0;
	int res[10];
	int j = strlen(pn);
	int idx = 2;
	cout > idx;
	for (int i = 0,len = strlen(pn);i  '9') { cout  *(p2)) return -1;
            else return 1;
        }
        p1++;
        p2++;
    }
    return 0;
   
}

重写strstr

char* caijimystrstr(const char* haystack, const char* needle)
{
    char* p1 = (char*)haystack;
    char* p2 = (char*)needle;
    char* tmp1;
    char* tmp2 = p2;
    while (*p1)
    {
        while (*p1 == *p2)
        {
            tmp1 = p1;
            for (int i = 0; i  
解析XML
 
bool xmlbuffer(const char* xmlbuf, const char* fieldname, char* value = 0, const size_t ilen = 0)
{
    if (xmlbuf == 0 || fieldname == 0) return false;
    //创建字段
    int lenfieldname = strlen(fieldname);
    //开辟空间
    char* sfieldname = new char[lenfieldname + 3];
    char* efieldname = new char[lenfieldname + 4];
    //初始化
    memset(sfieldname, 0, lenfieldname +3);  // 错误代码 memset(sfieldname, 0, sfieldname); 原因：new出来的空间不能用memset
    memset(efieldname, 0, lenfieldname +4);
    //创建字段
    strcpy(sfieldname, "");
    strcpy(efieldname, "");
    //找字段；
    char* start;
    char* end;
    start = (char*)strstr(xmlbuf, sfieldname);
    end = (char*)strstr(xmlbuf, efieldname);
    //没找到
    if (start == 0 || end == 0)
    {
        delete[] sfieldname;
        delete[] efieldname;
        return 0;
    }
    
    size_t vallen = (end - start - lenfieldname - 2);  //指针减去指针等于数值，表示的是从 start 到 end 的距离减去了 lenfieldname（ 的长度）和 2（ 的长度）。
    
    if (ilen == 0)
    {
        
        strncpy(value, start + lenfieldname + 2, vallen);
        value[vallen] = 0;
    }
    else if (vallen  lens)
    {
        my2strcpy(dest, src);
    }
    int i = 0;
    for (i = 0; i