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代码片段

#1、将字符串中的指定字符串替换为另一个指定的字符串。

std::string replace_space_any(std::string s, std::string o, std::string n) {
	size_t osize = o.size();
	size_t nsize = n.size();
	int o_number = 0;
	for (int pos = 0; pos < s.size(); ++pos) {
		if (!strncmp(s.data() + pos, o.data(), o.size())) {
			for (size_t j = 0; j < n.size(); ++j) {
				o_number++;
			}
			pos += o.size();
		}
	}

	int diff = nsize - osize;
	int new_len = s.size() + diff* o_number;
	if (new_len <= 0) {
		return "";
	}

	char* new_str = new char[new_len];
	memset(new_str, 0, new_len);

	int new_pos = 0;
	for (int pos = 0; pos < s.size();) {
		if (!strncmp(s.data() + pos, o.data(), o.size())) {
			for (size_t j = 0; j < n.size(); ++j) {
				new_str[new_pos++] = n[j];
			}
			pos += o.size();
		}
		else {
			new_str[new_pos] = s[pos];
			new_pos++;
			pos++;
		}
	}

	std::string res = new_str;
	delete[] new_str;
	return res;
}