有人可以帮我“结构”吗？ [英] Can someone help me with "struct"?
问题描述
我的教授要求我们这样做：
编写并运行一个构建名为part_rec的结构的程序。每个part_rec结构将是名为Robot_parts []的数据库（结构数组）中的记录。
每个part_rec结构由一个名为part_num的整数，一个名为part_name的字符串，一个名为part_quantity的整数和一个名为
的part_cost组成。 。一个名为void display（）的函数通过指针获取整个Robot_parts []数组，并在函数中显示此信息。
确保在函数中显示具有良好列标题和对齐的信息。
在main（）中，将Robot_parts []初始化为：
part_rec Robot_parts [] = {{7789，QTI，4， 12.95}，
{1654，bolt，4,0.34}，
{6931，nut，4,0.25}};
一旦在main（）中初始化，调用display（）函数并将指针地址传递给Robot_parts []作为其参数。
当我编译并运行时程序，没有结果
#include < iostream >
#include < 字符串 >
＃包括 < iomanip >
使用 命名空间标准
void display（）;
struct part_rec
{
int part_num;
string part_name;
int part_quantity;
double part_cost;
};
int main（）
{
char CH;
part_rec Robot_parts [] = {
{ 7789 ， QTI， 4 ， 12 。 95 }，
{ 1654 ， bolt， 4 ， 0 。 34 }，
{ 6931 ， nut， 4 ， 0 。 25 }
};
cout<< 输入'e'退出;
cin>> ch;
return 0 ;
}
void display（part_rec * Robot_parts []）
{
int i;
for （i = 0 ; i< 3; i ++）
cout<< setw（ 5 ）<< Robot_parts [i] - > part_num;
cout<< setw（ 7 ）<< Robot_parts [i] - > part_name;
cout<< setw（ 5 ）<< Robot_parts [i] - > part_quantity;
cout<< setw（ 10 ）<< Robot_parts [i] - > part_cost;
return ;
}
我的尝试：
N / A
那是因为你实际上没有调用你的显示/输出例程。也许你应该改变这个
part_rec Robot_parts [] = {
{7789，QTI，4,12.95}，
{1654，bolt，4,0.34}，
{6931，nut，4,0.25}
};
cout<<输入'e'退出;
cin>> ch;
to
part_rec Robot_parts [] = {
{7789，QTI，4,12.95}，
{1654，bolt，4,0.34}，
{6931 ，坚果，4,0.25}
};
显示（Robot_parts）;
cout<<输入'e'退出;
cin>> ch;
[edit]
这个： -
void display（part_rec * Robot_parts []）
{
int i;
for（i = 0; i< 3; i ++）
cout<< setw（5）<< Robot_parts [i] - > part_num;
cout<< setw（7）<<< Robot_parts [i] - > part_name;
cout<< setw（5）<<< Robot_parts [i] - > part_quantity;
cout<< setw（10）<< Robot_parts [i] - > part_cost;
返回;
}
会'更好'/？更正确的
void display（part_rec * Robot_parts []）
{
for（int i = 0; i< 3; i ++）
{
cout<< setw（5）<<< Robot_parts [i] - > part_num;
cout<< setw（7）<<< Robot_parts [i] - > part_name;
cout<< setw（5）<<< Robot_parts [i] - > part_quantity;
cout<< setw（10）<< Robot_parts [i] - > part_cost;
}
返回;
}
而不是硬编码3作为数组中元素的数量，你可能（制作你的程序）未来安全）
int numberOfParts = sizeof （Robot_parts）/ sizeof （Robot_parts [ 0 ]）;
然后使用它就像
for （ int i = 0 ; i< numberOfParts; i ++）
或将数组中的元素数传递给显示器（ ...）功能
[/ edit]
这样做
int numberOfParts = sizeof（Robot_parts）/ sizeof （Robot_parts [0]）;
i很好，但是，我不认为它可以在显示器内完成（...）所以，这意味着你做这样的事情
int numberOfParts = sizeof（Robot_parts）/ sizeof（Robot_parts [0]）;
显示（Robot_parts，numberOfParts）;
并将display（）的声明更改为
void display（part_rec * Robot_parts []，int numberOfParts）
[/ EDIT2]
My professor requires us to do:
Write and run a program that builds a struct called "part_rec". Each "part_rec" struct will be a record in a database (struct array) called Robot_parts[ ].
Each "part_rec" struct is composed of an integer called "part_num", a string called "part_name", an integer called "part_quantity" and a double called
"part_cost". A function called void display() takes the entire Robot_parts[ ] array in by pointer and displays this information in the function.
Make sure to display this information with good column headings and alignment in the function.
In main(), initialize Robot_parts[ ] as:
part_rec Robot_parts[ ] = {{ 7789, "QTI", 4, 12.95},
{1654, "bolt", 4, 0.34},
{6931, "nut", 4, 0.25}};
Once initialized in main(), call the display() function and pass a pointer address to Robot_parts[ ] as its argument.
As I compile&run the program, there are no results
#include <iostream>
#include <string>
#include<iomanip>
using namespace std;
void display();
struct part_rec
{
int part_num;
string part_name;
int part_quantity;
double part_cost;
};
int main()
{
char ch;
part_rec Robot_parts[ ] = {
{7789, "QTI", 4, 12.95},
{1654, "bolt", 4, 0.34},
{6931, "nut", 4, 0.25}
};
cout<<" enter 'e' to exit";
cin>>ch;
return 0;
}
void display(part_rec *Robot_parts[])
{
int i;
for(i = 0; i<3; i++)
cout<<setw(5)<<Robot_parts[i]->part_num;
cout<<setw(7)<<Robot_parts[i]->part_name;
cout<<setw(5)<<Robot_parts[i]->part_quantity;
cout<<setw(10)<<Robot_parts[i]->part_cost;
return;
}
What I have tried:
N/A
thats because you dont actually call your display/output routine. Perhaps you should change this
part_rec Robot_parts[ ] = { {7789, "QTI", 4, 12.95}, {1654, "bolt", 4, 0.34}, {6931, "nut", 4, 0.25} }; cout<<" enter 'e' to exit"; cin>>ch;
to
part_rec Robot_parts[ ] = { {7789, "QTI", 4, 12.95}, {1654, "bolt", 4, 0.34}, {6931, "nut", 4, 0.25} }; display(Robot_parts); cout<<" enter 'e' to exit"; cin>>ch;
[edit]
this :-
void display(part_rec *Robot_parts[]) { int i; for(i = 0; i<3; i++) cout<<setw(5)<<Robot_parts[i]->part_num; cout<<setw(7)<<Robot_parts[i]->part_name; cout<<setw(5)<<Robot_parts[i]->part_quantity; cout<<setw(10)<<Robot_parts[i]->part_cost; return; }
would be 'nicer' / ? more correct as
void display(part_rec *Robot_parts[]) { for(int i = 0; i<3; i++) { cout<<setw(5)<<Robot_parts[i]->part_num; cout<<setw(7)<<Robot_parts[i]->part_name; cout<<setw(5)<<Robot_parts[i]->part_quantity; cout<<setw(10)<<Robot_parts[i]->part_cost; } return; }
and instead of hardcoding 3 as the number of elements in the array, you could probably (to make your program future safe)
int numberOfParts = sizeof(Robot_parts) / sizeof(Robot_parts[0]);
and then use that like
for(int i = 0; i<numberOfParts; i++)
or pass the number of elements in the array into the display(...) function
[/edit]
[edit 2 - warning bells in my head]
doing this
int numberOfParts = sizeof(Robot_parts) / sizeof(Robot_parts[0]);
is fine, but, I dont think it can be done from within display(...) so, that means you do something like this
int numberOfParts = sizeof(Robot_parts) / sizeof(Robot_parts[0]); display(Robot_parts, numberOfParts);
and change the declaration of display() to
void display(part_rec *Robot_parts[], int numberOfParts)
[/edit2]
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