How to print dimensions of multidimensional array in C++
Create a function that prints multidimensional array size by dimensions i.e.:
Examples:
Input :
int a[2][3][4];
printDimensions(a);
Output :
2x3x4
Input :
int b[5][6];
printDimensions(a);
Output :
5x6
To solve this problem we should use template function to figure out the size of current array. Then we call this function recursively till the last dimension. For last dimension the boundary overridden template function should be used. The implementation of the idea:
CPP
#include <iostream>
template < typename T, size_t N>
void printDimensions( const T (&a)[N])
{
std::cout << N;
}
template < typename T, size_t N, size_t M>
void printDimensions( const T (&a)[N][M])
{
std::cout << N << "x";
printDimensions(a[0]);
}
int main()
{
int a[2][3][4];
printDimensions(a);
return 0;
}
|
Pay attention the order of two template functions. It won’t compile if you switch them.
There is one more way to get the same results by using language template features:
CPP
#include <iostream>
#include <type_traits>
template < typename T>
std::enable_if_t<std::rank<T>::value == 1>
printDimensions( const T& a)
{
std::cout << std::extent<T>::value;
}
template < typename T>
std::enable_if_t<std::rank<T>::value != 1>
printDimensions( const T& a)
{
std::cout << std::extent<T>::value << "x";
printDimensions(a[0]);
}
int main()
{
int a[2][3][4];
printDimensions(a);
return 0;
}
|
If you think that template names are too long to print you are not alone. There are short aliases in C++17:
std::extent_v for std::extent::value and std::rank_v for std::rank::value
Last Updated :
24 Jan, 2022
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