[C/C++标准库]_[初级]_[不使用正则替换和删除字符串]

场景:

1.在处理手机号码时，往往可能会遇到手机号里有-或,分割，如果去掉这些符号得到一个正常的数字字符串呢？

2.如果不用C++的string,纯C的话估计还得先计算替换后的字符串长度才能开始替换操作吧，其实用stl和C标准库结合实现,只暴露C接口还是比较方便的。没必要局限在只用纯C.

3.如果不想依赖第3放库时怎么办？

删除字符:

wstring ws(L"1-63-42-5 375-2-3");
ws.erase(remove(ws.begin(),ws.end(),L'-'),ws.end());
wcout << "ws: " << ws << endl;

删除字符串:

    
    char* ReplaceStr(const char* str, const char* old_flag, const char* new_flag)
{
    std::string new_str(str);
    size_t old_flag_length = strlen(old_flag);
    size_t new_flag_length = strlen(new_flag);

    size_t index = new_str.find(old_flag);
    while (index != std::string::npos)
    {
        new_str.replace(index,old_flag_length,new_flag);
        index = new_str.find(old_flag,index+new_flag_length);
    }
    return strdup(new_str.c_str());
}

    char* DeleteDelims(const char* str, const char* delims, const char* new_delims)
{
        char* temp = strdup(str);
        char *result = NULL;
        result = strtok(temp, delims);
        std::string new_str;
        while (result)
        {
            new_str.append(result);
            result = strtok(NULL, delims);
            if(new_delims && result)
            {
                new_str.append(new_delims);
            }
        }
        if(new_str.size())
        {
            return strdup(new_str.c_str());
        }
        return NULL;
}

用法:

1.删除字符串里的匹配字符串,删除 - 符号

DeleteDelims("192-2342-2343","-",NULL);

2.替换字符串,把两个空格替换为一个空格.

DeleteDelims("192  2342  2343"," "," ");

        const char* str1 = "156-1234-5678";
	const char* str2 = "0755-21331234";
	const char* str3 = "-0755-21331234";
	const char* str4 = "0755-21331234-";
	const char* str5 = "-0755-21331234-";

	char* str = DeleteDelims(str1, "-", NULL);
	ASSERT_FALSE(strcmp(str,"15612345678"));
	free(str);

	str = DeleteDelims(str2, "-", NULL);
	ASSERT_FALSE(strcmp(str,"075521331234"));
	free(str);

	str = DeleteDelims(str3, "-", NULL);
	ASSERT_FALSE(strcmp(str,"075521331234"));
	free(str);

	str = DeleteDelims(str4, "-", NULL);
	ASSERT_FALSE(strcmp(str,"075521331234"));
	free(str);

	str = DeleteDelims("0755-21331234--", "-", NULL);
	ASSERT_FALSE(strcmp(str,"075521331234"));
	free(str);

	str = ReplaceStr("0755-21331234--", "-", "ab");
	ASSERT_FALSE(strcmp(str,"0755ab21331234abab"));
	free(str);

	str = ReplaceStr("0755-21331234--", "-", "a-");
	ASSERT_FALSE(strcmp(str,"0755a-21331234a-a-"));
	free(str);

	str = DeleteDelims(str5, "-", NULL);
	ASSERT_FALSE(strcmp(str,"075521331234"));
	free(str);

	str = DeleteDelims("Name I  L", " ", NULL);
	ASSERT_FALSE(strcmp(str,"NameIL"));
	free(str);

	str = DeleteDelims("Name I  L", " ", " ");
	ASSERT_FALSE(strcmp(str,"Name I L"));
	free(str);

	str = DeleteDelims("-", "-", NULL);
	ASSERT_FALSE(str);