Compilare: main.cpp: In function 'int main()': main.cpp:6:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation] for(x=a,y=b;n--;x=X,y=Y) ^~~ main.cpp:7:42: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for' scanf("%Lf%Lf",&X,&Y),S+=x*Y-X*y;S+=x*b-a*y; ^ main.cpp:5:92: 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),freopen("aria.out","w",stdout),scanf("%Lf%Lf%Lf",&n,&a,&b); ^ main.cpp:5:92: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] main.cpp:5:92: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] main.cpp:7:41: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%Lf%Lf",&X,&Y),S+=x*Y-X*y;S+=x*b-a*y; ^