According to this consensus in the default allowed inputs thread, functions may output by writing to an out argument.
When outputting an array in languages like C/C++, where arrays are pointers to locations in memory, can we assume the memory at the output location to have been allocated and to be of a sufficient size to output the complete answer, or must the memory be allocated in the code?
Below are some example functions in C that output by modifying their parameters; please consider each case, and state which cases you'd consider acceptable.
// Fixed size
void one_to_ten(int*o){
for(int i=1; i<=10; i++)
o[i-1]=i;
}
// Output size is a function of input size
void mul_table(int*o,int*a,int m,int*b,int n){
for(int i=0; i<m; i++)
for(int j=0; j<n; j++)
o[i*n+j]=a[i]*b[j];
}
// Size of output is given
void roll_dice(int*res, int n){
for(int i=0; i<n; i++)
res[n]=rand()%6+1;
}
// Output has a variable size and a defined maximum size
void scramble(int*o, int seed){
srand(seed);
int r;
for(int i=0; (r=rand())&&i<128; i++)
o[i]=r;
}
