Compilare: main.cpp: In function 'int main()': main.cpp:11:29: warning: unused variable 'bac' [-Wunused-variable] double sum = 0.0 , no , bac; ^~~ main.cpp:12:32: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d%d\n",&n,&k); ^ main.cpp:13:30: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fgets (s , 1000010 , fin); ^ main.cpp:15:54: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%lf%lf%lf",&pc[i],&pi[i],&pb[i]); ^