"double(*)(string, double, double)"尝试传递函数C++时"double"转换错误
"double(*)(string, double, double)" to "double" conversion error when trying to pass a function C++
我对 c++ 相当陌生，我正在编写一个具有结构体的程序，以及 3 个名为 win_percentage、Wins_losses 和 winning_teams 的函数。这项任务的目的是创建一个程序，打印出 13 支学校球队及其记录，然后打印出获胜超过 .500 的球队。
我不断收到一个错误，说：
无法将"双 (*((std：：__cxx11：：字符串， double， double( {aka double (*((std：：：__cxx11：：basic_string， double， double(}' 转换为 参数"4"的"double"到"void wins_losses(std：：__cxx11：：string， 双，双，双('
wins_losses(学校1.名称，学校1.胜，学校1.负， win_percentage(;
当我尝试将win_percentage函数传递到其他函数时，会出现此问题。我如何解决这个问题？请帮忙哈哈
这是我的代码。(ps我将为该程序制作一个for循环(
#include <iostream>
#include<string>
using namespace std;
struct Team
{
string name;
int wins;
int losses;
};
double win_percentage (string , double , double );
void wins_losses (string , double , double , double );
void winning_teams (string , double , double , double );
int main() {
Team school1 = {"Bethune-Cookman", 11, 3};
Team school2 = {"Coppin State", 5, 9};
Team school3 = {"Delaware State", 1, 13};
Team school4 = {"Florida A&M", 6, 8};
Team school5 = {"Hampton", 11, 4};
Team school6 = {"Howard", 6, 8};
Team school7 = {"Maryland Eastern Shore", 2, 12};
Team school8 = {"Morgan State", 6, 8};
Team school9 = {"North Carolina A&T", 10, 4};
Team school10 = {"North Carolina Central", 8, 6};
Team school11 = {"Norfolk State", 10, 4};
Team school12 = {"Savannah State", 10, 4};
Team school13 = {"South Carolina State", 6, 8};
cout<< "MEAC MENS BASKETBALL TEAMS CONFERENCE STANDINGS"<< endl;
cout<< school1.name<<" "<<school1.wins<<"-"<<school1.losses<< endl;
cout<< school2.name<<" "<<school2.wins<<"-"<<school2.losses<< endl;
cout<< school3.name<<" "<<school3.wins<<"-"<<school3.losses<< endl;
cout<< school4.name<<" "<<school4.wins<<"-"<<school4.losses<< endl;
cout<< school5.name<<" "<<school5.wins<<"-"<<school5.losses<< endl;
cout<< school6.name<<" "<<school6.wins<<"-"<<school6.losses<< endl;
cout<< school7.name<<" "<<school7.wins<<"-"<<school7.losses<< endl;
cout<< school8.name<<" "<<school8.wins<<"-"<<school8.losses<< endl;
cout<< school9.name<<" "<<school9.wins<<"-"<<school9.losses<< endl;
cout<< school10.name<<" "<<school10.wins<<"-"<<school10.losses<< endl;
cout<< school11.name<<" "<<school11.wins<<"-"<<school11.losses<< endl;
cout<< school12.name<<" "<<school12.wins<<"-"<<school12.losses<< endl;
cout<< school13.name<<" "<<school13.wins<<"-"<<school13.losses<< endl;
cout<<"TEAMS WINNING PERCENTAGE"<<endl;
win_percentage(school1.name,school1.wins,school1.losses);
win_percentage(school2.name,school2.wins,school2.losses);
win_percentage(school3.name,school3.wins,school3.losses);
win_percentage(school4.name,school4.wins,school4.losses);
win_percentage(school5.name,school5.wins,school5.losses);
win_percentage(school6.name,school6.wins,school6.losses);
win_percentage(school7.name,school7.wins,school7.losses);
win_percentage(school8.name,school8.wins,school8.losses);
win_percentage(school9.name,school9.wins,school9.losses);
win_percentage(school10.name,school10.wins,school10.losses);
win_percentage(school11.name,school11.wins,school11.losses);
win_percentage(school12.name,school12.wins,school12.losses);
win_percentage(school13.name,school13.wins,school13.losses);
cout<<"TEAMS WITH WINNING RECORDS"<<endl;
wins_losses(school1.name,school1.wins,school1.losses, win_percentage);
wins_losses(school2.name,school2.wins,school2.losses,win_percentage);
wins_losses(school3.name,school3.wins,school3.losses,win_percentage);
wins_losses(school4.name,school4.wins,school4.losses,win_percentage);
wins_losses(school5.name,school5.wins,school5.losses,win_percentage);
wins_losses(school6.name,school6.wins,school6.losses,win_percentage);
wins_losses(school7.name,school7.wins,school7.losses,win_percentage);
wins_losses(school8.name,school8.wins,school8.losses,win_percentage);
wins_losses(school9.name,school9.wins,school9.losses,win_percentage);
wins_losses(school10.name,school10.wins,school10.losses,win_percentage);
wins_losses(school11.name,school11.wins,school11.losses,win_percentage);
wins_losses(school12.name,school12.wins,school12.losses,win_percentage);
wins_losses(school13.name,school13.wins,school13.losses,win_percentage);
winning_teams(school1.name,school1.wins,school1.losses,win_percentage);
winning_teams(school2.name,school2.wins,school2.losses,win_percentage);
winning_teams(school3.name,school3.wins,school3.losses,win_percentage);
winning_teams(school4.name,school4.wins,school4.losses,win_percentage);
winning_teams(school5.name,school5.wins,school5.losses,win_percentage);
winning_teams(school6.name,school6.wins,school6.losses,win_percentage);
winning_teams(school7.name,school7.wins,school7.losses,win_percentage);
winning_teams(school8.name,school8.wins,school8.losses,win_percentage);
winning_teams(school9.name,school9.wins,school9.losses,win_percentage);
winning_teams(school10.name,school10.wins,school10.losses,win_percentage);
winning_teams(school11.name,school11.wins,school11.losses,win_percentage);
winning_teams(school12.name,school12.wins,school12.losses,win_percentage);
winning_teams(school13.name,school13.wins,school13.losses,win_percentage);
return 0;
}
double win_percentage(string a, double b, double c){
double x;
x == b / (b + c);
cout<< a<<" "<<x<<endl;
}
void wins_losses( string e, double f, double g, double h){
cout<< e<< "Record is"<<f<<"-"<<g<< h<<endl;
}
void winning_teams(string w, int f, int y, double z){
if ( z >.500){
cout<< w<<" "<<f<< "-"<<y<< " "<< z<< endl;
}
}
我注意到这里有一些问题。第一：
double win_percentage(string a, double b, double c){
double x;
x == b / (b + c);
cout<< a<<" "<<x<<endl;
}
该函数不会：
- 赋值给变量
x，因为它使用的是相等运算符。 - 返回一个值，因此函数的调用方无法访问
x。这是未定义的行为，因为非 void 函数没有返回。
下一个：
winning_teams(school1.name,school1.wins,school1.losses,win_percentage);
此调用尝试将函数指针传递给需要双精度的函数。相反，请使用函数指针语法，甚至更好的是，使用 std::function 。
但是，我怀疑你真的需要在这里传递一个函数。如果要传递函数的结果，请执行以下操作：
winning_teams(school1.name,
school1.wins,
school1.losses,
win_percentage(/* Parameters to the function */));
当你调用wins_losses时，你传递win_percentage作为参数：
wins_losses(school1.name,school1.wins,school1.losses, win_percentage);
函数wins_losses需要double，但你传递对函数的引用，即 win_percentage .
这就是原因。
因此，要么调用win_percentage以便将其返回值用作参数，要么传递双精度值：
wins_losses(school1.name,school1.wins,school1.losses, win_percentage(school1.name,school1.wins,school1.losses));
wins_losses(school1.name,school1.wins,school1.losses,5.0);
您在win_percentage中使用比较运算符而不是赋值运算符
double win_percentage(string a, double b, double c){
double x;
x == b / (b + c);
cout<< a<<" "<<x<<endl;
}
尝试使用：x = (b/(b+c((
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