Compilare: user.cpp: In function ‘int main()’: user.cpp:21:15: warning: unused variable ‘a’ [-Wunused-variable] int n,i,j,a,b,nr=0; ^ user.cpp:21:17: warning: unused variable ‘b’ [-Wunused-variable] int n,i,j,a,b,nr=0; ^ user.cpp:19:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nrtri.in","r",stdin); ^ user.cpp:20:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("nrtri.out","w",stdout); ^ user.cpp:22:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:24:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i]); ^ user.cpp: In function ‘int find(int, int, int)’: user.cpp:16:12: warning: ‘elem’ may be used uninitialized in this function [-Wmaybe-uninitialized] return elem; ^ user.cpp: In function ‘int main()’: user.cpp:28:18: warning: ‘elem’ may be used uninitialized in this function [-Wmaybe-uninitialized] nr=nr+find(j+1,n,v[i]+v[j])-j; ^