我一直专注于我最新的编程练习,以实现模板打印出2D数组。我只允许修改实现文件。 (即主文件和头文件必须保持不变)我不得不根据对象采用的模板类型使用随机数填充数组。有没有可行的方法利用rand()根据类型生成随机数?任何帮助将不胜感激。谢谢!
RowAray.h:
#ifndef ROWARAY_H
#define ROWARAY_H
template<class T>
class RowAray{
protected:
int size;
T *rowData;
public:
RowAray(int);
virtual ~RowAray();
int getSize()const{return size;}
T getData(int i)const{
if(i>=0&&i<size)return rowData[i];
else return 0;}
void setData(int,T);
};
#endif /* ROWARAY_H */
Table.h:
#ifndef TABLE_H
#define TABLE_H
#include "RowAray.h"
template<class T>
class Table{
protected:
int szRow;
int szCol;
RowAray<T> **columns;
public:
Table(unsigned int,unsigned int);
Table(const Table<T> &);
virtual ~Table();
int getSzRow()const {return szRow;}
int getSzCol()const {return szCol;}
T getData(int,int)const;
void setData(int,int,T);
Table<T> operator+(const Table<T> &);
};
#endif /* TABLE_H */
RowAray.cpp:
#include "RowAray.h"
#include <cstdlib>
template<class T>
RowAray<T>::RowAray(int r) {
size = r;
rowData = new T[r];
for (int i = 0; i < size; i++) {
rowData[i] = static_cast<T>((rand() % 90 + 10));
}
}
template<class T>
RowAray<T>::~RowAray() {
delete []rowData;
}
template<class T>
void RowAray<T>::setData(int i, T value) {
rowData[i] = value;
}
Table.cpp:
#include "Table.h"
template<class T>
Table<T>::Table(unsigned int r, unsigned int c) {
szRow = r;
szCol = c;
columns = new RowAray<T>*[r];
for(int i = 0; i < r; i++) {
columns[i] = new RowAray<T>(c);
}
}
template<class T>
Table<T>::Table(const Table<T> &t) {
szRow = t.getSzRow();
szCol = t.getSzCol();
columns = new RowAray<T>*[t.getSzRow()];
for(int i = 0; i < t.getSzRow(); i++) {
columns[i] = new RowAray<T>(t.getSzCol());
}
for (int i = 0; i < t.getSzRow(); i++) {
for (int j = 0; j < t.getSzCol(); j++) {
columns[i]->setData(j, t.getData(i, j));
}
}
}
template<class T>
Table<T>::~Table() {
for (int i = 0; i < szRow; i++) {
delete []columns[i];
}
delete []columns;
}
template<class T>
Table<T> Table<T>:: operator+(const Table<T> &t) {
Table<T> tab;
tab.szRow = t.getSzRow();
tab.szCol = t.getSzCol();
for(int i = 0; i < t.getSzRow(); i++) {
for (int j = 0; j <t.getSzCol(); j++) {
tab.columns[i]->setData(j, this->getData(i,j) + t.getData(i,j));
}
}
return tab;
}
main.cpp:
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <iomanip>
using namespace std;
//User Libraries
#include "Table.h"
//Global Constants
//Function Prototype
template<class T>
void prntRow(RowAray<T> *,int);
template<class T>
void prntTab(const Table<T> &);
//Execution Begins Here!
int main(int argc, char** argv) {
//Initialize the random seed
srand(static_cast<unsigned int>(time(0)));
//Declare Variables
int rows=3,cols=4;
//Test out the Row with integers and floats
RowAray<int> a(3);RowAray<float> b(4);
cout<<"Test the Integer Row "<<endl;
prntRow(&a,3);
cout<<"Test the Float Row "<<endl;
prntRow(&b,4);
//Test out the Table with a float
Table<float> tab1(rows,cols);
Table<float> tab2(tab1);
Table<float> tab3=tab1+tab2;
cout<<"Float Table 1 size is [row,col] = ["
<<rows<<","<<cols<<"]";
prntTab(tab1);
cout<<"Float Table 2 size is [row,col] = ["
<<rows<<","<<cols<<"]";
prntTab(tab2);
cout<<"Float Table 3 size is [row,col] = Table 1 + Table 2 ["
<<rows<<","<<cols<<"]";
prntTab(tab3);
//Exit Stage Right
return 0;
}
template<class T>
void prntRow(RowAray<T> *a,int perLine){
cout<<fixed<<setprecision(1)<<showpoint<<endl;
for(int i=0;i<a->getSize();i++){
cout<<a->getData(i)<<" ";
if(i%perLine==(perLine-1))cout<<endl;
}
cout<<endl;
}
template<class T>
void prntTab(const Table<T> &a){
cout<<fixed<<setprecision(1)<<showpoint<<endl;
for(int row=0;row<a.getSzRow();row++){
for(int col=0;col<a.getSzCol();col++){
cout<<setw(8)<<a.getData(row,col);
}
cout<<endl;
}
cout<<endl;
}
从您的问题中不完全清楚,但假设您想要以不同的方式为不同类型生成随机值,您可以使用模板函数的特化:
template <class T>
T random_value(); // no definition
template <>
float random_value<float>()
{
return float(random()) / RAND_MAX; // number in [0, 1)
}
template <>
int random_value<int>()
{
return random();
}
template <>
uint64_t random_value<uint64_t>()
{
return (uint32_t(random()) << 32) | uint32_t(random());
}
然后在RowArray::RowArray
内你只需使用:
rowdata[i] = random_value<T>();
要将相关的特化因素放在一起(例如所有整数类型),请查看std::enable_if
。
第二种方法是在C ++ 17中使用if constexpr
和std::is_same_v
。例如,在RowArray::RowArray
构造函数中,您可以执行以下操作:
for (int i = 0; i < size; ++i)
{
if constexpr (std::is_same_v<T, float>)
row[i] = /* whatever you want for float case */
else if constexpr (std::is_same_v<T, int>)
row[i] = /* whatever you want for int case*/
else
static_assert(sizeof(T) == 0, "unsupported type");
}
看看type_traits
标题,看看如何测试所有整数类型等。
最后,看看C ++ random
库http://www.cplusplus.com/reference/random/,以避免在使用随机值时出现常见错误。