SDL_Log outputting ??" when trying to output a string - c++

Question

I've been trying to send a log in the console to make sure the player was created, but here is the results:
Here is the code along the problematic part:
SDL_Log("%s has %i hp out of %i", player1.name, player1.health, player1.maxhealth);
systemValues.h:
// Core Libraries and Headers
// - Global includes
#include <SDL.h>
#include <SDL_image.h>
#include <stdio.h>
#include <string>
#include <typeinfo>
// Defines
#define GRAPHICS "../resources/"
struct Player
{
std::string sprite;
std::string name;
int level;
int size;
int health;
int maxhealth;
int magicpower; // Magic Points
int damages;
int armor;
int magic;
};
struct Enemy
{
std::string sprite;
std::string name;
int level;
int size;
int health;
int maxhealth;
int magicpower; // Magic Points
int damages;
int armor;
int magic;
};
Player createPlayer(std::string name);
Enemy createEnemy(std::string name, int level);
int damagePlayer(Player target, int damages);
int damageEnemy(Enemy target, int damages);
void close();
main.cpp:
// Local includes
// - Custom Headers
#include "systemValues.h"
// Screen constants and dimensions. (TODO: MOVE TO A PROPER HEADER FILE.)
const int SCREEN_WIDTH = 640;
const int SCREEN_HEIGHT = 480;
// The window that is rendered to
SDL_Window* window = NULL;
// Quit being false means the application is running and did not request to quit
bool quit = false;
// Event handler
SDL_Event e;
// The surface contained by the window
SDL_Surface* screenSurface = NULL;
// Main function
int main(int argc, char* args[])
{
// Initializing SDL
if (SDL_Init(SDL_INIT_VIDEO)<0)
{
SDL_Log("SDL could not initialize! SDL_Error: %s\n", SDL_GetError());
}
else
{
// Creating the window
window = SDL_CreateWindow("SDL Tutorial", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
if (window == NULL)
{
SDL_Log("The window could not be created! SDL_Error: %s\n", SDL_GetError());
}
else
{
Player player1 = createPlayer("Avarthar");
Enemy enemy1 = createEnemy("Blob", 1);
// Get the window surface
screenSurface = SDL_GetWindowSurface(window);
// While the application is running
while (!quit){
while (SDL_PollEvent(&e) != 0)
{
// User requests quit
if (e.type == SDL_QUIT)
{
quit = true;
}
// Checks for a key being pressed down
else if (e.type == SDL_KEYDOWN)
{
switch(e.key.keysym.sym)
{
// Checks if the key is F
case SDLK_f:
player1.health = damagePlayer(player1, 5);
SDL_Log("%s has %i hp out of %i", player1.name, player1.health, player1.maxhealth); // TODO - Remove the test line
break;
case SDLK_ESCAPE:
quit = true;
break;
}
}
}
// Test if player is created
if (player1.name == "Avarthar")
{
SDL_FillRect(screenSurface, NULL, SDL_MapRGB(screenSurface->format, (player1.health*-1+100*2), player1.health*2, 0));
}
else
{
SDL_FillRect(screenSurface, NULL, SDL_MapRGB(screenSurface->format, 255, 255, 255));
}
// Update the surface
SDL_UpdateWindowSurface(window);
}
}
}
close();
// Return 0 to terminate the program
return 0;
}
// Creates a player with the given varables
Player createPlayer(std::string name)
{
Player player;
player.sprite = "";
player.name = name;
player.level = 1;
player.size = 32;
player.health = 100;
player.maxhealth = 100;
player.magicpower = 100;
player.damages = 1;
player.armor = 0;
player.magic = 1;
return player;
}
Enemy createEnemy(std::string name, int level)
{
Enemy enemy;
enemy.sprite = "";
enemy.name = name;
enemy.level = level;
enemy.size = 32;
enemy.health = 100;
enemy.maxhealth = 100;
enemy.magicpower = 100; // Magic Points
enemy.damages = 1;
enemy.armor = 0;
enemy.magic = 1;
return enemy;
}
// Deals damage to the target of type Player
int damagePlayer(Player target, int damages)
{
target.health -= damages;
// Checks whether the target is in the health range or not
if (target.health < 0)
target.health = 0;
if (target.health > target.maxhealth)
target.health = target.maxhealth;
return target.health;
}
// Deals damage to the target of type Enemy
int damageEnemy(Enemy target, int damages)
{
target.health -= damages;
// Checks whether the target is in the health range or not
if (target.health < 0)
target.health = 0;
if (target.health > target.maxhealth)
target.health = target.maxhealth;
return target.health;
}
void close()
{
// Wait 0.1 seconds
SDL_Delay(100);
// Clear the window from the memory
SDL_DestroyWindow(window);
// Quit the SDL subsystems
SDL_Quit();
}
What I tried so far:
I tried with &player1.name and it didn't change anything.
I also tried with only SDL_Log("%s", player1.name); and it instead wrote a single ? in the outputs.
The color changing according to the player1.health is working without any problem, but as soon as I try getting and sending the name in the SDL_Log it sends the outputs shown in the screenshot above.

Answer 1

SDL_Log cannot do std::string. Use player1.name.c_str(). This should have triggered a warning, check your compiler flags. – Quentin
Thanks for the quick answer and also thanks for noticing another problem that I had with my compiler ^^