std::string::npos是C++标准库中string类的静态成员变量,它表示一个无效的或者不存在的字符串位置或索引。这个值在string类中通常用于查找或搜索某个子字符串或字符的位置,当find()或rfind()等函数无法找到所需的子字符串或字符时,它们会返回std::string::npos作为标记表示查找失败。 std::string::npos的
函数substr() 定义 substr(size_type _Off = 0,size_type _Count = npos) _Off——所需的子字符串的起始位置。字符串中第一个字符的索引为 0,默认值为0。 _Count——复制的字符数目 返回值——一个子字符串,从其指定的位置开始 第二个参
void replace_all(std::string& s, const std::string& search, const std::string& replace) { for (size_t pos = 0; ; pos += replace.length()) { pos = s.find(search, pos); if (pos == std::string::npos) break; s.erase(pos, search.length()); s.insert(pos, replace); } }...
=Json::npos)for(unsignedi=0;i<root["empt"].arr.size();i++)printf("%f\n",root["empt"][i].floVal);if(root["first Name"]!=Json::npos)printf("%s\n",root["first Name"].strVal.c_str());if(root["ept"]["ko"]!=Json::npos)printf("ept:ko:%lf\n",root["ept"]["ko"]....
In case none were found, equals std::string::npos.Example of use:string utf_invalid = "\xe6\x97\xa5\xd1\x88\xfa"; auto invalid = find_invalid(utf_invalid); assert (invalid == 5);This function is typically used to make sure a UTF-8 string is valid before processing it with ...
find(sample_start, 0); while (sample_begin != std::string::npos) { out_samples_begin.push_back(sample_begin); const size_t search_start = sample_begin + sample_start.size(); sample_begin = data_str.find(sample_start, search_start); } if (out_samples_begin.size() == 0) { ...
if (arg.find(headInfo) == std::string::npos) { if (strncat_s(msg.update, sizeof(msg.update), arg.c_str(), strlen(arg.c_str()) + 1) != EOK) { LOG(ERROR) << "SetMessageToMisc strncat_s failed"; return; } if (strncat_s(msg.update, sizeof(msg.update), "...
#include <bitset>#include <iostream>#include <string>intmain(){// string search functions return npos if nothing is foundstd::strings="test";if(s.find('a')==s.npos)std::cout<<"no 'a' in 'test'\n";// functions that take string subsets as arguments// use npos as the "all the...
#include <iostream>#include <stdexcept>#include <string>#include <variant>structDemon{Demon(int){}Demon(constDemon&){throwstd::domain_error("copy ctor");}Demon&operator=(constDemon&)=default;};intmain(){std::variant<int, Demon>var{42};std::cout<<std::boolalpha<<"index == npos: "<<...
string x; int tag,n; cin>>x>>tag>>n; while(n--){ string str; cin>>str; if(tag==1){ size_t pos=str.find(x); if(pos!=string::npos){ cout<<str<<endl; } } else{ string temp,tx; for(size_t i=0;i<str.size();++i){ temp+=tolower(str[i]); } for(size_t i=0...