Compilare: user.cpp:41:25: warning: integer constant is too large for its type [enabled by default] mat[j][j+i]=20000000000000000000; ^ user.cpp: In function ‘int main()’: user.cpp:20:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%lld",&n); ^ user.cpp:23:37: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%lld",&arr[i+1]); ^