Compilare: main.cpp: In function 'int main()': main.cpp:2:169: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] #define solve char marc[262145]; int tati[262145];int main(){int n,i,last=0,k,x=1,np=0;FILE*fi,*fo;fi=fopen("euler.in","r");fo=fopen("euler.out","w");fscanf(fi,"%d",&n);while(fscanf(fi,"%d",&k)!=EOF){if(marc[k]==0){if(tati[k]!=0 || k==np)x=0;tati[k]=last;marc[k]=1;}if(marc[last]==1 && k==tati[last])marc[last]=0;last=k;if(np==0)np=k;}if(x==1){fprintf(fo,"DA\n");for(i=1;i<=n;i++)fprintf(fo,"%d ",tati[i]);}else fprintf(fo,"NU");fclose(fi);fclose(fo);return 0;} ^ main.cpp:5:41: note: in expansion of macro 'solve' /*////*/solve/////// ^~~~~