C C++比较：
1.
Scanf printf 函数
Cin cout可不指定输入输出格式，消耗时间多
2.
Stdio :standard input output .h——head
Stdio.h ——include sth about input and output (cstdio)
#include<xxx> use stdio.h
Math.h (cmath)
String.h (cstring)
3.
Only one entrance
Int main(){
Return 0;
}
4.
Int a,b;
Scanf(“%d%d”,&a,&b);
Printf(“%d”,a+b);
5.
C++ downward compatible C
