Compilare: user.cpp: In function ‘int main()’: user.cpp:8:70: warning: unused variable ‘ok’ [-Wunused-variable] int r,co,i,j,x,y,nx,ny,f=1,b=0,st=0,dr=0,mij,last=-1,ix,iy,fx,fy,ok=0; ^ user.cpp:6:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("barbar.in","r",stdin); ^ user.cpp:7:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("barbar.out","w",stdout); ^ user.cpp:9:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d\n",&r,&co); ^ user.cpp:12:22: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(ch[i]+1); ^ user.cpp:22:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("\n"); ^ user.cpp:81:21: warning: ‘fy’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (viz[fx][fy]==1) ^ user.cpp:81:21: warning: ‘fx’ may be used uninitialized in this function [-Wmaybe-uninitialized] user.cpp:8:61: warning: ‘iy’ may be used uninitialized in this function [-Wmaybe-uninitialized] int r,co,i,j,x,y,nx,ny,f=1,b=0,st=0,dr=0,mij,last=-1,ix,iy,fx,fy,ok=0; ^ user.cpp:8:58: warning: ‘ix’ may be used uninitialized in this function [-Wmaybe-uninitialized] int r,co,i,j,x,y,nx,ny,f=1,b=0,st=0,dr=0,mij,last=-1,ix,iy,fx,fy,ok=0; ^ In file included from /usr/include/stdio.h:934:0, from /usr/include/c++/4.8/cstdio:42, from user.cpp:1: In function ‘char* gets(char*)’, inlined from ‘int main()’ at user.cpp:12:22: /usr/include/i386-linux-gnu/bits/stdio2.h:230:28: warning: call to ‘__gets_warn’ declared with attribute warning: please use fgets or getline instead, gets can't specify buffer size [enabled by default] return __gets_warn (__str); ^ /tmp/cc3ExdwH.o: In function `main': user.cpp:(.text.startup+0x90): warning: the `gets' function is dangerous and should not be used.