I'm trying to write program that create squere for string. Squere has to be larger then string.length(). If there is word 'C++' I need 2x2 array to fill it inside. So I have written code
#include <cmath>
#include <cstdlib>
#include <iostream>
#include <string>
using namespace std;
int pole(int &a,const int* l);
int main(){
string code;
cin >> code;
int wall=1;
pole(wall,code.length());
cout << wall;
system("PAUSE");
return 0;
}
int pole(int &a,const int* l){
if (a*a > l) return a;
else {
a+=1;
pole(a,l);
}
}
I bet that using pointer with recunrency save a lot of memory but I can't compile it. I'm trying to understand compilers error but is 2 hard for me ;/
Here is compiler list of errors
> in main()
11 25 Error] invalid initialization of non-const reference of type 'int&' from an rvalue of type 'int (*)(int&, const int*)'
6 5> [Error] in passing argument 1 of 'int pole(int&, const int*)'
in pole() 17 12
>[Error] ISO C++ forbids comparison between pointer and
> integer [-fpermissive]
Here:
pole(pole, code.length());
You are passing as the second variable the result of length()
, which is of type std::string::size_type
, which the function pole
accepts a pointer to int
. Those two types are incompatible.
The second problem is that one branch of your if
statement inside pole
does not contain a return
statement, thus giving your program Undefined Behavior.
You may want to change your function pole
this way:
int pole(int &a, std::string::size_type l) {
// ^^^^^^^^^^^^^^^^^^^^^^
// Also, passing by reference is unnecessary here
if (a*a > static_cast<int>(l)) return a;
// ^^^^^^^^^^^^^^^^
// Just to communicate that you are aware of the
// signed-to-unsigned comparison here
else {
a+=1;
return pole(a,l);
// ^^^^^^
// Do not forget this, or your program will have Undefined Behavior!
}
}
Here you can see your modified program compile and run.