C++语言程序设计课后练习.doc

练习2．1 设整数42486，请定义一个变量，初始化之，并以8进制与16进制数输出，如果将该整数定义成无符号短整数，当以有符号数输出时，结果是什么，请用补码概念解释。解：#include iostream.h void main() { //本题原考虑在16位机器上实验目前多为32位机器，故已过时。 int a = 42486; cout oct a endl hex a endl; unsigned b = 42486; cout dec (signed)b endl; }2．2 取圆周率为3．1415926，分别输入半径为40和928．335，求圆面积．要求各数据按域宽13位输出，先输出圆周率和半径，再输出其面积。解：#include iostream.h #include iomanip.h const double pi = 3.1415926; void main() { double radius1, radius2; cout please input two numbers:\n; cin radius1 radius2; cout setw(10) pi setw(10) radius1 setw(10) (pi*radius1*radius1) endl setw(10) pi setw(10) radius2 setw(10) (pi*radius2*radius2) endl; }2．3 将常数e(2．718281828)作为常量定义，然后输出其10位有效位数的浮点数、定点方式和8位小数位表示的数，以及指数形式和8位小数位表示的数：解：#include iostream.h #include iomanip.h const double e = 2.718281828; void main() { cout setprecision(10) e endl setiosflags(ios::fixed) setprecision(8) e endl setiosflags(ios::scientific) e endl; }2．4 设学生常数为500，编程输出下列结果(引号也要输出)。　　　　“How many students here?”　　　　“500”解：#include iostream.h void main() { cout \How many students here?\\n \500\\n; }2．5 用sizeof操作符，求出表2—2中各数据类型的字节长度，并按：　　　　size of char 1 byte　　　　size of int　2 byte　　的格式打印输出。解：#include iostream.h void main() { cout size of char sizeof(char) byte\n size of unsigned char sizeof(unsigned char) byte\n size of signed char sizeof(signed char) byte\n size of int sizeof(int) byte\n size of unsigned sizeof(unsigned) byte\n size of signed sizeof(signed) byte\n size of short sizeof(short) byte\n size of unsigned short sizeof(unsigned short) byte\n size of long sizeof(long) byte\n size of signed long sizeof(signed long) byte\n size of unsigned long sizeof(unsigned long) byte\n size of float sizeof(float) byte\n size of double sizeof(double) byte\n size of long do