Some C++ data types, their format specifiers, and their most common bit widths are as follows:
- Int ("%d"): 32 Bit integer
- Long ("%ld"): 64 bit integer
- Char ("%c"): Character type
- Float ("%f"): 32 bit real value
- Double ("%lf"): 64 bit real value
Reading
To read a data type, use the following syntax:
scanf("`format_specifier`", &val)
For example, to read a character followed by a double:
char ch;
double d;
scanf("%c %lf", &ch, &d);
For the moment, we can ignore the spacing between format specifiers.
Printing
To print a data type, use the following syntax:
printf("`format_specifier`", val)
For example, to print a character followed by a double:
char ch = 'd';
double d = 234.432;
printf("%c %lf", ch, d);
Note: You can also use cin and cout instead of scanf and printf; however, if you are taking a million numbers as input and printing a million lines, it is faster to use scanf and printf.
Input Format
Input consists of the following space-separated values: int, long, char, float, and double, respectively.
Output Format
Print each element on a new line in the same order it was received as input. Note that the floating point value should be correct up to 3 decimal places and the double to 9 decimal places.
Sample Input
3 12345678912345 a 334.23 14049.30493
Sample Output
3
12345678912345
a
334.230
14049.304930000
#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
int a;
long long b;//变量数据类型的选择：应该使用long long int，又可简写为long long
char c;
float d;
double e;
cin >> a >> b >> c >> d >> e;
cout << a << endl;
cout << b << endl;
cout << c << endl;
/*我们在这里主要用到其中两个：fixed 和 showpoint。
首先说fixed，以定点方式显示实数，即显示整数部分*/
cout <<setiosflags(ios::fixed)<< setprecision(3)<<d<< endl;
cout<<setiosflags(ios::fixed)<<setprecision(9) <<e;
return 0;
}主要考察基本变量吧，注意long long ；
