I have been trying to return an array of strings for a function for a couple of days to no avail. While I was searching around StackOverflow, I found that it would be a better idea to have a parameter that will be assigned the value of an array. So, here is my code example (not the actual usage, but a mockup of how I am trying to use the function). I am sorry if the code is a bit sloppy. I have been testing things out with it for a while.
void splitOn(string message, string delim, string***toCh) {
string** rString = new string*;
string lArr[numberOf(message, delim)+1];
for(int index=0; index<numberOf(message, delim)+2; index++) {
lArr[index]=message.substr(0, message.find(delim)).c_str();
message = message.substr(message.find(delim)+1, message.length());
rString[index]=&lArr[index];
cout << "IN LOOP "<<*rString[index]<<endl;
}
rString[numberOf(message, string(delim))] = &message;
toCh=&rString;
}
int main(){
string***arr;
splitOn("fox.over.lazy.dog", ".", arr);
cout << **arr[0]<<endl;
Note:
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numberOf() takes a string and a delimiter(string) and returns how many times the delimiter is found within the string.
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strings are from std::string
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lArr (the local array within the loop) and *rString all give correct output.
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Although I am trying to assign the array to a parameter, learning how to return an array is more appealing to me.
I could hack this together with a file and getLine(), but I would prefer to learn how to properly do this.
You’re trying to return local variables, which will never work. You and your caller need to agree on how to allocate the return value. In C++ as the commenters mention this would normally be done by passing a reference to a vector to handle your allocation for you.
In C you have two options, you can either get the caller to pass in a big enough allocation, or use multiple calls to malloc in the callee (not forgetting the calls to free in the caller!)
For instance, if you pass a writable character array, you can simply overwrite the separator characters with null characters to split it up into individual strings without having to allocate new copies.