我正在尝试从函数返回一个向量，但我似乎遇到了一些问题......
目前，这是我得到的最好的：
int* OptimizedSkillLevels(int skillLevel, const int numSkills, int duration, FragmentOptimizationParameters FOP){
//some code to work with some things was here
vector<int> skills(numSkills);
int skillIncrement = 0;
while (skillLevel > FOP.levelDifference){
skills[skillIncrement%numSkills] += FOP.levelDifference;
skillLevel-= FOP.levelDifference;
skillIncrement++;
}
skills[skills.size()-1] += skillLevel;
//at this point, the vector skills is full of the correct values, which is what really matters.
}
int* skillsArr = &skills[0];
return skillsArr;
}
虽然当我从这个函数调用中访问它时，这似乎给了我垃圾值：
cout << OptimizedSkillLevels(skillLevels[i], userMaxNumSkills, durations[i], FOPs[FOPindex])[j] << ", ";
具体来说，无论-17891602是什么，我每次都会得到[j]。
然后我尝试按如下方式转换为矢量：
vector<int> OptimizedSkillLevels(int skillLevel, const int numSkills, int duration, FragmentOptimizationParameters FOP){
//some code to work with some things was here
vector<int> skills(numSkills);
int skillIncrement = 0;
while (skillLevel > FOP.levelDifference){
skills[skillIncrement%numSkills] += FOP.levelDifference;
skillLevel-= FOP.levelDifference;
skillIncrement++;
}
skills[skills.size()-1] += skillLevel;
//at this point, the vector skills is full of the correct values, which is what really matters.
}
return skills;
}
使用函数原型：
vector<int> OptimizedSkillLevels(int skillLevel, int numSkills, int duration, FragmentOptimizationParameters FOP);
但是我遇到了很多错误，包括这个（在原型的一行）：
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59): error C2143: syntax error : missing ';' before '<'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
这些，在将我的函数的返回类型更改为vector之前没有出现过......所以我真的不知道发生了什么。
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59): error C2143: syntax error : missing ';' before '<'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(73): error C2872: 'vector' : ambiguous symbol
1> could be 'c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59) : int vector'
1> or 'c:\program files (x86)\microsoft visual studio 11.0\vc\include\vector(655) : std::vector'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(73): error C2143: syntax error : missing ';' before '<'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(73): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(73): error C2086: 'int vector' : redefinition
1> c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59) : see declaration of 'vector'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(74): error C2872: 'vector' : ambiguous symbol
1> could be 'c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59) : int vector'
1> or 'c:\program files (x86)\microsoft visual studio 11.0\vc\include\vector(655) : std::vector'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(74): error C2143: syntax error : missing ';' before '<'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(74): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(74): error C2086: 'int vector' : redefinition
1> c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59) : see declaration of 'vector'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(84): error C2065: 'FOPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(84): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(85): error C2065: 'FOPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(85): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(86): error C2065: 'FOPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(86): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(87): error C2065: 'FOPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(87): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(88): error C2065: 'FOPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(88): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(89): error C2065: 'FOPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(89): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(91): error C2065: 'FCPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(91): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(92): error C2065: 'FCPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(92): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(93): error C2065: 'FCPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(93): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(94): error C2065: 'FCPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(94): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(95): error C2065: 'FCPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(95): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(96): error C2065: 'FCPs' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(96): error C2228: left of '.push_back' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(169): warning C4244: 'return' : conversion from 'const double' to '__int64', possible loss of data
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(192): warning C4244: 'argument' : conversion from 'double' to '__int64', possible loss of data
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(195): warning C4244: '=' : conversion from 'double' to 'int', possible loss of data
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(196): warning C4244: '=' : conversion from 'double' to 'int', possible loss of data
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(197): warning C4244: 'argument' : conversion from 'double' to '__int64', possible loss of data
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(202): warning C4244: '+=' : conversion from 'double' to 'int', possible loss of data
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(203): warning C4244: '+=' : conversion from 'double' to 'int', possible loss of data
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(215): error C2872: 'vector' : ambiguous symbol
1> could be 'c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59) : int vector'
1> or 'c:\program files (x86)\microsoft visual studio 11.0\vc\include\vector(655) : std::vector'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(215): error C2062: type '__int64' unexpected
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(216): error C2872: 'vector' : ambiguous symbol
1> could be 'c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59) : int vector'
1> or 'c:\program files (x86)\microsoft visual studio 11.0\vc\include\vector(655) : std::vector'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(216): error C2062: type '__int64' unexpected
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(217): error C2872: 'vector' : ambiguous symbol
1> could be 'c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59) : int vector'
1> or 'c:\program files (x86)\microsoft visual studio 11.0\vc\include\vector(655) : std::vector'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(217): error C2062: type '__int64' unexpected
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(229): error C2065: 'optimalCosts' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(229): error C2228: left of '.size' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(231): error C2065: 'optimalCosts' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(231): error C2228: left of '.resize' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(232): error C2065: 'skillLevels' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(232): error C2228: left of '.resize' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(233): error C2065: 'durations' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(233): error C2228: left of '.resize' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(236): error C2065: 'optimalCosts' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(239): error C2065: 'optimalCosts' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(239): error C2228: left of '.size' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(242): error C2065: 'optimalCosts' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(243): error C2065: 'optimalCosts' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(244): error C2065: 'skillLevels' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(245): error C2065: 'durations' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(251): error C2065: 'optimalCosts' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(251): error C2228: left of '.size' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(252): error C2065: 'optimalCosts' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(252): error C2065: 'skillLevels' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(252): error C2065: 'durations' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(265): error C2872: 'vector' : ambiguous symbol
1> could be 'c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59) : int vector'
1> or 'c:\program files (x86)\microsoft visual studio 11.0\vc\include\vector(655) : std::vector'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(265): error C2062: type 'int' unexpected
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(266): error C2872: 'vector' : ambiguous symbol
1> could be 'c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(59) : int vector'
1> or 'c:\program files (x86)\microsoft visual studio 11.0\vc\include\vector(655) : std::vector'
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(266): error C2062: type 'int' unexpected
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(269): error C2065: 'optimalCosts' : undeclared identifier
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(269): error C2228: left of '.size' must have class/struct/union
1> type is ''unknown-type''
1>c:\users\vasu\documents\visual studio 11\projects\composing calc\composing calc\composing calc.cpp(269): fatal error C1903: unable to recover from previous error(s); stopping compilation
1>
任何人都可以提供有关返回矢量的正确方法或某种解决方法的任何帮助，我们将不胜感激。
答案 0 :(得分：5)
您的第一种方法返回指向不再存在的对象的指针。这显然永远不会起作用。
你的第二种方法是正确的。只需修复语法错误。你有#include <vector>吗？你有using namespace std;吗？