C++ primer(第五版）第1章习题答案
初学C++ primer，记录整理，使用ubuntu14.04和GNU编译器，答案参考于github
第一章 开始
1.1
文件命名约定:参考这里（https://www.cnblogs.com/yang666/p/6515623.html）
GCC 5.4 头文件后缀: h, hh, hpp, H, tcc (for shared template code);
源文件后缀: cp, cpp, CPP, C, cc, cxx, c++.
1.2
返回值为255，含义是超出了退出状态的范围，具体参考这里
1.3
#include
int main()
{
std::cout << "Hello, World" << std::endl;
return 0;
}
1.4
#include
int main()
{
std::cout << "Enter two numbers:" << std::endl;
int v1 = 0, v2 = 0;
std::cin >> v1 >> v2;
std::cout << "The product of " << v1 << " and " << v2
<< " is " << v1 * v2 << std::endl;
return 0;
}
1.5
#include
int main()
{
std::cout << "Enter two numbers:" << std::endl;
int v1 = 0, v2 = 0;
std::cin >> v1 >> v2;
std::cout << "The product of ";
std::cout << v1;
std::cout << " and ";
std::cout << v2;
std::cout << " is ";
std::cout << v1 * v2;
std::cout << std::endl;
return 0;
}
1.6
不合法，去掉前两个分号，分号代表语句结束，会导致后两个输出运算符左侧没有ostream对象
1.7
/*
* comment pairs /* */ cannot nest.
* ''cannot nest'' is considered source code,
* as is the rest of the program
*/
int main()
{
return 0;
}
1.8
第三句不合法，在分号前添加双引号即可
1.9
#include
int main()
{
int sum = 0, val = 50;
while (val <= 100) {
sum += val;
++val;
}
std::cout << "Sum of 50 to 100 inclusive is " << sum << std::endl;
return 0;
}
1.10
#include
int main()
{
int val = 10;
while (val >= 0) {
std::cout << val << std::endl;
--val;
}
return 0;
}
1.11
#include
int main()
{
int small = 0, big = 0;
std::cout << "please input two integers:";
std::cin >> small >> big;
if (small > big) {
int tmp = small;
small = big;
big = tmp;
}
while (small <= big) {
std::cout << small << " ";
++small;
}
std::cout << std::endl;
return 0;
}
1.12
-100到100的和,sum为0
1.13
Ex1.9:
#include
int main()
{
int sum = 0;
for (int i = 50; i <= 100; ++i)
sum += i;
std::cout << "the sum is: " << sum << std::endl;
return 0;
} Ex1.10:
#include
int main()
{
for (int i = 10; i >= 0; --i)
std::cout << i << " ";
std::cout << std::endl;
return 0;
} Ex1.11:
#include
int main()
{
int small = 0, big = 0;
std::cout << "please input two integers:";
std::cin >> small >> big;
if (small > big) {
int tmp = small;
small = big;
big = tmp;
}
for (int i = small; i <= big; ++i)
std::cout << i << " ";
std::cout << std::endl;
return 0;
}
1.14
注意：for语句中定义的变量在循环结束之后是不可以使用的。
1.15
语法错误
类型错误
声明错误
1.16
#include
int main()
{
int sum = 0;
for (int value = 0; std::cin >> value; )
sum += value;
std::cout << sum << std::endl;
return 0;
}
1.17
都相等，输出总共次数，都不重复，输出每个值重复一次。
1.18
1.19
见1.10
1.20
#include
#include "./1/Sales_item.h"
int main()
{
Sales_item item;
while (std::cin >> item) std::cout << item << std::endl;
return 0;
} 我这边需要指定-std=c++0x参数
1.21
#include
#include "./1/Sales_item.h"
int main()
{
Sales_item item1, item2;
std::cin >> item1 >> item2;
if (item1.isbn() == item2.isbn()) {
std::cout << item1 + item2 << std::endl;
return 0;
}
else {
std::cerr << "Data must refer to same ISBN." << std::endl;
return -1;
}
}
1.22
#include
#include "./1/Sales_item.h"
int main()
{
Sales_item total;
if (std::cin >> total) {
Sales_item trans;
while (std::cin >> trans) {
if (total.isbn() == trans.isbn())
total += trans;
else {
std::cout << total << std::endl;
total = trans;
}
}
std::cout << total << std::endl;
}
else {
std::cerr << "No data?!" << std::endl;
return -1;
}
return 0;
}
1.23
#include
#include "../include/Sales_item.h"
int main()
{
Sales_item currItem, valItem;
if (std::cin >> currItem) {
int cnt = 1;
while (std::cin >> valItem) {
if (valItem.isbn() == currItem.isbn())
++cnt;
else {
std::cout << currItem << " occurs " << cnt << " times "
<< std::endl;
currItem = valItem;
cnt = 1;
}
}
std::cout << currItem << " occurs " << cnt << " times " << std::endl;
}
return 0;
}
1.24
1.25
