Eroare de compilare: user.cpp:5:18: error: ‘double y1’ redeclared as different kind of symbol double ans,x1,x2,y1,y2; ^ In file included from /usr/include/features.h:357:0, from /usr/include/i386-linux-gnu/c++/4.8/bits/os_defines.h:39, from /usr/include/i386-linux-gnu/c++/4.8/bits/c++config.h:420, from /usr/include/c++/4.8/cstdio:41, from user.cpp:1: /usr/include/i386-linux-gnu/bits/mathcalls.h:243:1: error: previous declaration of ‘double y1(double)’ __MATHCALL (y1,, (_Mdouble_)); ^ user.cpp: In function ‘int main()’: user.cpp:13:27: warning: format ‘%lf’ expects argument of type ‘double*’, but argument 3 has type ‘double (*)(double)throw ()’ [-Wformat=] scanf("%lf%lf",&x1,&y1); ^ user.cpp:15:7: error: cannot convert ‘double(double)throw ()’ to ‘double’ in assignment yy=y1; ^ user.cpp:19:27: error: invalid operands of types ‘double’ and ‘double(double)throw ()’ to binary ‘operator*’ ans+=x1*y2-x2*y1; ^ user.cpp:21:15: error: assignment of function ‘double y1(double)’ y1=y2; ^ user.cpp:21:15: error: cannot convert ‘double’ to ‘double(double)throw ()’ in assignment user.cpp:23:19: error: invalid operands of types ‘double’ and ‘double(double)throw ()’ to binary ‘operator*’ ans+=x1*yy-xx*y1; ^ user.cpp:8:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("aria.in","r",stdin); ^ user.cpp:9:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("aria.out","w",stdout); ^ user.cpp:12:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:13:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf",&x1,&y1); ^ user.cpp:18:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lf%lf",&x2,&y2); ^