code tips

Common header files

math
iomanip
algorithm
fstream

Common file inputs (summarized earlier)
define input streams

ifstream fin;
fin.open("filename.txt");
int x;
fin>>x;

Summary of c/c++ output format
Set the field width setw ()
Set the precision after the decimal point setprecision() Automatically fill
0 after the digit ,cmp) cmp needs to be written by yourself Rewrite the function to change the parameter type abs can be rewritten as the return value of double type