C++ Programming Practice Problems

Created at 17/12/2016 by Zcalory

It is time to devote myself to coding to prepare for my pursuits and further study. This repository is created to write codes in C++ language.
##Stage 1: Programming problems on my textbook: C++ Programming Foundations(Fourth Edition) ###Note: ####条件编译/conditional compilation

#if 常量表达式  
程序文本  
#endif

若“常量表达式”为1，则“程序文本”参与编译。

#if constant    
program  
#endif  

If the "constant" equals 1 then compiles the "program".

#if 常量表达式  
程序文本1  
#else  
程序文本2  
#endif  

若“常量表达式”为1，则“程序文本1”参与编译,否则“程序文本2”参与编译。

#if constant    
program1    
#else    
program2    
#endif

If the "constant" equals 1 then compiles the "program1", otherwise compiles the "program2".

#ifndef 标识符    
#define 标识符   
程序文本    
#endif  

若“标识符”未定义，则编译“程序文本”；若“标识符”已定义，则“程序文本”被忽略。

#ifndef identifier    
#define identifier    
program    
#endif  

if the "identifier" has never been defined, compiles the "program"; otherwise ingores it.

The third kind of conditional compilation often used in the ".h" files to avoid the error of "redefinition".
And to avoid this problem, try to separate statement and definition:

In the ".h" files, writes only data type(s) and function statement(s);
in the ".cpp" files, writes definition(s) of variable and funtion.

数组的动态内存分配

利用 new 与 delete 进行动态内存的分配与删除
动态创建一维数组：

int num=20；//num可作为变量，并随时对其进行赋值
int *A=NULL；//利用NULL对指针进行初始化
A=new int [num];
...  
delete []A;//释放内存

动态创建二维数组：

动态创建double[Row][Col]二维数组
int ROW = 2;
int COL = 3;
double **pvalue  = new double* [ROW]; // 为行分配内存

// 为列分配内存
for(int i = 0; i < COL; i++) {
    pvalue[i] = new double[COL];
}
//释放内存
for(int i = 0; i < COL; i++) {
    delete[] pvalue[i];//需对每行进行一次释放
}
delete [] pvalue;