I am working on a game for the 3ds and I want it to be a cmd type game (I just felt like it). I am trying to have this char move to whatever x and y int number I have but I am getting a error. This is my code.
/*
Hello World example made by Aurelio Mannara for libctru
This code was modified for the last time on: 12/12/2014 21:00 UTC 1
*/
#include <3ds.h>
#include <stdio.h>
#include <string.h>
int main(int argc, char **argv)
{
gfxInitDefault();
char player[1024] = "\x1b[";
int tesx = 1;
char tesxx = tesx '0';
char ot[] = ";";
char oty[] = "H0";
int test = 3;
char testt = test '0';
//Initialize console on top screen. Using NULL as the second argument tells the console library to use the internal console structure as current one
consoleInit(GFX_TOP, NULL);
strcat(player, tesxx);
strcat(player, ot);
strcat(player, testt);
strcat(player, oty);
//Move the cursor to row 15 and column 19 and then prints "Hello World!"
//To move the cursor you have to print "\x1b[r;cH", where r and c are respectively
//the row and column where you want your cursor to move
//The top screen has 30 rows and 50 columns
//The bottom screen has 30 rows and 40 columns
printf(player);
// Main loop
while (aptMainLoop())
{
//Scan all the inputs. This should be done once for each frame
hidScanInput();
//hidKeysDown returns information about which buttons have been just pressed (and they weren't in the previous frame)
u32 kDown = hidKeysDown();
if (kDown & KEY_START) break; // break in order to return to hbmenu
// Flush and swap framebuffers
gfxFlushBuffers();
gfxSwapBuffers();
//Wait for VBlank
gspWaitForVBlank();
}
gfxExit();
return 0;
}
This is my error. I am very new to C so i'm sorry if this is an easy bug. I tried searching but I couldn't find anything online.
C:/Users/Jeremy/Desktop/gaame/source/main.c:24:9: warning: 'strcat' offset 0 is out of the bounds [0, 0] [-Warray-bounds]
24 | strcat(player, testt);
| ^~~~~~~~~~~~~~~~~~~~~
C:/Users/Jeremy/Desktop/gaame/source/main.c:22:9: warning: '__builtin_stpcpy' offset 0 is out of the bounds [0, 0] [-Warray-bounds]
22 | strcat(player, tesxx);
| ^~~~~~~~~~~~~~~~~~~~~
CodePudding user response:
The function strcat
requires both of its arguments to be a pointer to a valid string, which is, by definition, a sequence of characters terminated by a null character.
However, in the line
strcat(player, tesxx);
the second function argument tesxx
is not a pointer to a valid string. It is instead a simple char
.
I therefore suggest that you change the lines
strcat(player, tesxx);
strcat(player, ot);
strcat(player, testt);
strcat(player, oty);
to the following:
snprintf( player, sizeof player, "%c%s%c%s", tesxx, ot, testt, oty );
See the function snprintf
for further information.
CodePudding user response:
Consider the signature of strcat
.
char *strcat( char *dest, const char *src );
It does not take a char *
and a char
, but rather two char *
, and will expect two null-terminated strings.
CodePudding user response:
strcat
takes 2 string pointers:
char *strcat(char *dest, const char *src);
In strcat(player, tesxx)
and strcat(player, testt)
you pass a char
instead of a char *
, invoking undefined behavior. In order to append a single char to a C string in an array with extra space, you can write explicit code:
#include <string.h>
void append_char(char *dest, char c) {
size_t len = strlen(dest);
dest[len ] = c;
dest[len] = '\0';
}
Or you can use strncat
defined in <string.h>
as:
char *strncat(char *dest, const char *src, size_t n);
This function appends at most n
chars from src
at the end of dest
. You can pass the address of a char
and a length of 1
:
#include <string.h>
void append_char(char *dest, char c) {
strncat(dest, &c, 1);
}
Yet for your code, it seems much simpler to use snprintf
:
char player[1024]; // probably too large
int tesx = 1;
int test = 3;
consoleInit(GFX_TOP, NULL);
// draw a `0` at screen coordinates tesx,test
snprintf(player, sizeof player, "\x1b[%d;%dH0", tesx, test);