我正在尝试创建一个比较搜索功能，该功能可以根据字符将两个字符串进行比较。例如：
输入：“ ca” 姓氏字段下的结构矢量内容（排序矢量）（索引/值）：0 /“汽车”，1 /“道路” 结果：“在索引0找到名称-汽车”
我希望用户能够使用任意数量的字符。然后，程序应将提供的搜索条件与向量的内容进行比较，并返回所有匹配项的索引。
到目前为止，我还没有实现任何成功的尝试，这是到目前为止的代码。另外，我对C ++还是很陌生。
// Function for searching through an array for a string value.
int searchArray(std::vector<playerdata> (&people), std::string name) {
int loc = -1;
int counter = 0;
int index = 0;
//when loc is no longer -1, that means the person has been found
for (int i = 0; i < people.size(); i++)
for(int k = 0; k < name.length(); k++) {
std::cout << name[k-1] << std::endl;
std::cout << people[i].lastname[k-1] << std::endl;
std::cout << counter << std::endl;
std::cout << "" << std::endl;
if(name[k-1] == people[i].lastname[k-1]) {
counter++;
}
if(counter == name.length()) {
loc = i;
break;
}
}
//if (people[i].lastname.compare(name) == 0)
//loc = i;
return loc;
}
这是我在控制台中看到的内容，我正在使用cout进行调试：
What is player 1 information (F/L/DOB (DD/MM/YYY)), Seperate using a space):
hello sunshine
What is player 2 information (F/L/DOB (DD/MM/YYY)), Seperate using a space):
good bye
Pick from the available options:
1 - Input Data:
2 - Display Original Data:
3 - Sort Data:
4 - Display Sorted Data:
5 - Search By Last Name:
6 - Exit The Program;
3
Array Sorted!!!
Pick from the available options:
1 - Input Data:
2 - Display Original Data:
3 - Sort Data:
4 - Display Sorted Data:
5 - Search By Last Name:
6 - Exit The Program;
4
Player 1: good bye
Player 2: hello sunshine
Pick from the available options:
1 - Input Data:
2 - Display Original Data:
3 - Sort Data:
4 - Display Sorted Data:
5 - Search By Last Name:
6 - Exit The Program;
5
Enter the name to search:
bye
b
b
0
y
y
1
e
e
2
b
s
3
y
u
4
e
n
4
Player Found: good bye
Enter the name to search:
by
y
b
0
y
s
1
Player Found: good bye
Enter the name to search:
b
The player was not found, try again.
Enter the name to search:
sun
u
b
0
n
y
1
u
s
1
Player Found: hello sunshine
Enter the name to search:
sunshine
u
b
0
n
y
1
s
e
1
h
1
i
h
1
n
i
1
e
n
1
u
s
1
n
u
2
s
n
2
h
s
2
i
h
2
n
i
2
e
n
2
The player was not found, try again.
Enter the name to search:
编辑：正如您从我的控制台输出中看到的那样，当代码不应该这样做时，它会返回真正的比较。一个示例是is（e == n）的最后一个比较。答案应该是错误的，但始终会返回true。
使用注释中建议的代码后，我仍然无法使我的代码按预期工作并出现以下错误：
||=== Build file: "no target" in "no project" (compiler: unknown) ===|
E:\Coding\Cplus_work\assignmentseven.cpp||In function 'int main()':|
E:\Coding\Cplus_work\assignmentseven.cpp|68|warning: NULL used in arithmetic [-Wpointer-arith]|
E:\Coding\Cplus_work\assignmentseven.cpp|158|warning: NULL used in arithmetic [-Wpointer-arith]|
c:\mingw\lib\gcc\mingw32\8.2.0\include\c++\bits\predefined_ops.h||In instantiation of 'bool __gnu_cxx::__ops::_Iter_pred<_Predicate>::operator()(_Iterator) [with _Iterator = __gnu_cxx::__normal_iterator<playerdata*, std::vector<playerdata> >; _Predicate = searchArray(std::vector<playerdata>&, std::__cxx11::string&)::<lambda(std::__cxx11::string&)>]':|
c:\mingw\lib\gcc\mingw32\8.2.0\include\c++\bits\stl_algo.h|120|required from '_RandomAccessIterator std::__find_if(_RandomAccessIterator, _RandomAccessIterator, _Predicate, std::random_access_iterator_tag) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<playerdata*, std::vector<playerdata> >; _Predicate = __gnu_cxx::__ops::_Iter_pred<searchArray(std::vector<playerdata>&, std::__cxx11::string&)::<lambda(std::__cxx11::string&)> >]'|
c:\mingw\lib\gcc\mingw32\8.2.0\include\c++\bits\stl_algo.h|161|required from '_Iterator std::__find_if(_Iterator, _Iterator, _Predicate) [with _Iterator = __gnu_cxx::__normal_iterator<playerdata*, std::vector<playerdata> >; _Predicate = __gnu_cxx::__ops::_Iter_pred<searchArray(std::vector<playerdata>&, std::__cxx11::string&)::<lambda(std::__cxx11::string&)> >]'|
c:\mingw\lib\gcc\mingw32\8.2.0\include\c++\bits\stl_algo.h|3930|required from '_IIter std::find_if(_IIter, _IIter, _Predicate) [with _IIter = __gnu_cxx::__normal_iterator<playerdata*, std::vector<playerdata> >; _Predicate = searchArray(std::vector<playerdata>&, std::__cxx11::string&)::<lambda(std::__cxx11::string&)>]'|
E:\Coding\Cplus_work\assignmentseven.cpp|35|required from here|
c:\mingw\lib\gcc\mingw32\8.2.0\include\c++\bits\predefined_ops.h|283|error: no match for call to '(searchArray(std::vector<playerdata>&, std::__cxx11::string&)::<lambda(std::__cxx11::string&)>) (playerdata&)'|
E:\Coding\Cplus_work\assignmentseven.cpp|33|note: candidate: 'searchArray(std::vector<playerdata>&, std::__cxx11::string&)::<lambda(std::__cxx11::string&)>'|
E:\Coding\Cplus_work\assignmentseven.cpp|33|note: no known conversion for argument 1 from 'playerdata' to 'std::__cxx11::string&' {aka 'std::__cxx11::basic_string<char>&'}|
E:\Coding\Cplus_work\assignmentseven.cpp||In function 'bool sortArray(const playerdata&, const playerdata&)':|
E:\Coding\Cplus_work\assignmentseven.cpp|28|warning: control reaches end of non-void function [-Wreturn-type]|
||=== Build failed: 1 error(s), 8 warning(s) (0 minute(s), 0 second(s)) ===|
我使用的确切代码：
// Function for searching through an array for a string value.
int searchArray(std::vector<playerdata> (&people), std::string (&name))
{
auto it = std::find_if(people.begin(), people.end(), [&name](std::string& person){
return person.find(name) != std::string::npos;
});
if(it != people.end()) {
return std::distance(people.begin(), it);
} else {
return -1;
}
}
答案 0 :(得分：2)
可能的主要问题是，您尝试访问lastname[k-1]时访问k=0和find_if，这会导致UB。
在继续工作之前，请开始学习STL algorithms。考虑到这一点，仅使用std::string::find和#include <algorithm>
#include <iostream>
#include <vector>
#include <string>
struct playerdata
{
std::string lastname;
playerdata(std::string lastname) :
lastname(std::move(lastname))
{
}
};
int searchArray(std::vector<playerdata>& people, const std::string& name)
{
auto it = std::find_if(people.cbegin(), people.cend(), [&name](const playerdata& player){
return player.lastname.find(name) != std::string::npos;
});
if(it != people.end())
return std::distance(people.cbegin(), it);
else
return -1;
}
即可完成您的任务：
{{1}}
}
答案 1 :(得分：0)
`
SearchArray(std::vector<playerdata>& people, const std::string& keyWord)
{
int loc = -1;
// Use a better variable name to explain its purpose instead of `i`
// so you and other people like us can understand its meaning much faster
for (int vectorIndex = 0; vectorIndex < people.size(); vectorIndex++)
{
// if length of the name is bigger than a lastname it can`t be a match so just continue
if (keyWord.length() > people[vectorIndex].lastname.length())
{
continue;
}
int counter = 0;
int charIndexKeyWord = 0;
// Use a better variable name to explain its purpose instead of `k`
for (int charIndexIarget = 0; charIndexIarget < people[vectorIndex].lastname.length(); charIndexIarget++)
{
// Your for loop starts from 0 but you're trying to use [k-1] in your code
// you shouldn't do that, because in the first iteration of the loop it will indicate -1 [k-1]
// but it starts with 0,
//std::cout << keyWord[charIndexKeyWord] << std::endl;
//std::cout << people[vectorIndex].lastname[charIndexIarget] << std::endl;
//std::cout << counter << std::endl;
//std::cout << "" << std::endl;
// This is part of your code which needs improvment
if (keyWord[charIndexKeyWord] == people[vectorIndex].lastname[charIndexIarget])
{
counter++;
charIndexKeyWord++;
}
else
{
// If you keep your code as it is, it will may also consider matches like susnhine `sun` because
// so you need to make some improvements to get rid of it.
// if you have already founded a match but next word is not a match then you need to start looking from the beginning
if (counter != 0)
{
counter = 0;
charIndexKeyWord = 0;
}
}
if (counter == keyWord.length())
{
loc = vectorIndex;
}
}
if (loc != -1)
{
break;
}
}
return loc;
}