This question already has answers here:
Initialize multidimensional array with zeros
(7 answers)
Expression does not evaluate to a constant
(1 answer)
Variable Length Array (VLA) in C++ compilers
(2 answers)
Why aren't variable-length arrays part of the C++ standard?
(10 answers)
Closed 2 months ago.
I am trying to initialize a 2d array (matrix) to 0 but, cant do it:
int longestCommonSubsequence(string text1, string text2) {
int len1=0;
len1=text1.length()+1;
int len2=0;
len2=text2.length()+1;
int dp[len1][len2]={0};
Error:
Line 8: Char 16: error: variable-sized object may not be initialized
int dp[len1][len2]={0};
^~~~
1 error generated.
I want initialize the matrix while declaring it. I do not want to use for loop.
Variable sized arrays are not standard C++, for arrays of constant length you just use value-initialisation syntax:
int arr[4][4]{};
Alternatively, use C++ collections of variable length:
int rows = 4;
int columns = 4;
std::vector<std::vector<int>> vec(rows, std::vector<int>(columns));
This question already has answers here:
C++ : Creating an array with a size entered by the user
(3 answers)
How to create a dynamic array of integers
(8 answers)
Closed 1 year ago.
I know variable length arrays are not allowed in c++. My code is currently as follows:
int main(){
int t;
cin >> t;
double h[t];
}
How can I create an array with length t then?
Edit: the assignment only allows char, bool, int and double. Vector isn't allowed. When I tried to compile it, it says ISO C++ forbids variable length array 'h'.
This question already has answers here:
how to create a contiguous 2d array in c++?
(7 answers)
Closed 3 years ago.
OK, this question seems to be silly but bear with me. When I trying to create a 2D array in C++, it gave me some warnings (len is an integer):
double a[len][len];
// warning: variable length arrays are a C99 feature
// warning: variable length array used
So I tried another:
double **a = new double[len][len];
// error: only the first dimension of an allocated array may have dynamic size
// read of non-const variable 'len' is not allowed in a constant expression
How can I do it correctly in C++11?
double** a=new double*[len];
for(int i=0;i<len;++i)
{
a[i]=new double[len];
}
Are there any restrictions on what you can use? If you're planning to do array manipulations I'd say just use [Eigen] (http://eigen.tuxfamily.org/index.php?title=Main_Page)
This question already has answers here:
How to convert vector to array
(10 answers)
C++ vector<vector<double> > to double **
(3 answers)
Closed 4 years ago.
I have a variable std::vector<std::vector<float>> I want to pass this variable to a function which accepts array of array of float **float. I was wondering if there is any way to do this?
This question already has answers here:
C++11: Correct std::array initialization?
(5 answers)
Why can't simple initialize (with braces) 2D std::array? [duplicate]
(1 answer)
Closed 5 years ago.
I am early in c++. I want to define an 3d std::array in c++. when i define bellow array:
std::array<std::array<std::array<double,3>,4>, 4> DownSide = {
{{0,0.51,0.35},{0,0.51,0.35},{0,0.51,0.35},{0,0.51,0.35}},
{{0,0.51,0.35},{0,0.51,0.35},{0,0.51,0.35},{0,0.51,0.35}},
{{0,0.51,0.35},{0,0.51,0.35},{0,0.51,0.35},{0,0.51,0.35}},
{{0,0.51,0.35},{0,0.51,0.35},{0,0.51,0.35},{0,0.51,0.35}}
};
I see this error:
error: too many initializers for ‘std::array<std::array<std::array<double, 3ul>, 4ul>, 4ul>’
};
I googled this error find i mistak in numer brackets, but i dont know and find how must i write them.
How must i do?