保持简单,对于一维阵列,以下是一个:
#include <iostream>
template <size_t N> int sign(int(&arr)[N], int i)
{
return (arr[i] >= 0) ? +1 : -1 ;
}
int main(int argn, char** argv)
{
const int SIZE = 2;
int (*arr1d) = new int[SIZE];
arr1d[0] = 12;
arr1d[1] = -1;
std::cout << "sign 0 : " << sign(arr1d, 0) << std::endl ;
std::cout << "sign 1 : " << sign(arr1d, 1) << std::endl ;
}
但这不会编译:
Sign.cpp:17:50: error: no matching function for call to âsign(int*&, int)â
std::cout << "sign 1 : " << sign(arr1d, 1) << std::endl ;
^
Sign.cpp:3:29: note: candidate: template<long unsigned int N> int sign(int (&)[N], int)
template <size_t N> int sign(int(&arr)[N], int i)
^~~~
Sign.cpp:3:29: note: template argument deduction/substitution failed:
Sign.cpp:17:50: note: mismatched types âint [N]â and âint*â
std::cout << "sign 1 : " << sign(arr1d, 1) << std::endl ;
不
有什么建议吗?
2D情况下的相同错误:
#include <iostream>
template <size_t M, size_t N> int sign(int(&arr)[M][N], int i, int j)
{
return (arr[i][j] >= 0) ? +1 : -1 ;
}
int main(int argn, char** argv)
{
const int SIZE = 2;
int (*arr2d)[SIZE] = new int[SIZE][SIZE];
arr2d[0][0] = 12;
arr2d[0][1] = -1;
arr2d[1][0] = 32;
arr2d[1][1] = -4;
std::cout << "sign 0 1: " << sign(arr2d, 0, 1) << std::endl ;
}