[C + +] using Xcode to write C + + programs [3] Constants

Use Xcode to write C + + programs [3] Constants

Here are some of the basic data meanings:

75         // int75u        // unsigned int75l        // long75ul       // unsigned long 75lu       // unsigned long 

3.14159    // 3.141596.02e23    // 6.02 x 10^231.6e-19    // 1.6 x 10^-193.0        // 3.0 

3.14159L   // long double6.02e23f   // float 

‘z‘        // 单个字符

"How do you do?"  // 字符串

一些符号的含义:


bool类型以及指针

booltrue;boolfalse;intnullptr;


const变量

#include <iostream>using namespacestd;Const DoublePI =3.14159;Const CharNewLine ='\ n';intMain () {DoubleR=5.0;//radius  DoubleCircle; Circle=2* PI *R; cout<<Circle; cout<< newline;

Macro definition:

#include <iostream>usingnamespace  std; #define PI 3.14159#define NEWLINE ' \ n 'int  main ()  {double r=5.0;               // radius  Double Circle;   2 * PI * r;   << Circle;   << NEWLINE;}

 

[C + +] using Xcode to write C + + programs [3] Constants