- 第一题
直接上代码：
#include <iostream>
using namespace std;
int main() {
int a, b;
cin >> a;
cin >> b;
int sum = 0;
for(int i=a;i <= b;i++)
{
sum += i;
}
cout << sum;
return 0;
}
运行结果：
2
9
44
- 第二题
#include <iostream>
#include <array>
const int ArSize = 101;
int main() {
std::array<long double, ArSize> factorials;
factorials[0] = factorials[1] = 1L;
for(int i=2;i<ArSize;i++)
factorials[i] = i * factorials[i - 1];
for(int i=0;i<ArSize;i++)
std::cout << i << "! = " << factorials[i] << std::endl;
return 0;
}
运行结果：
92! = 1.24384e+142
93! = 1.15677e+144
94! = 1.08737e+146
95! = 1.033e+148
96! = 9.91678e+149
97! = 9.61928e+151
98! = 9.42689e+153
99! = 9.33262e+155
100! = 9.33262e+157
数量太多，只列举一些结果。
- 第三题
#include <iostream>
int main() {
int a;
int sum = 0;
std::cin >> a;
while (a != 0)
{
sum += a;
std::cin >> a;
}
std::cout << sum;
return 0;
}
运行结果：
5
6
7
2
0
20
- 第四题
#include <iostream>
const int money = 100;
const float Daphne = 0.1;
const float CLeo = 0.05;
int main() {
float sum_d = 0.0;
float sum_c = 0.0;
float more; // 盈利
float now = money; // 当前存款
int year = 0; // 年数
while (sum_c <= sum_d)
{
sum_d += money * Daphne;
more = now * CLeo;
now += more;
sum_c += more;
year += 1;
}
std::cout << "year: " << year << std::endl;
std::cout << "Daphne: " << sum_d << std::endl;
std::cout << "CLeo: " << sum_c << std::endl;
return 0;
}
运行结果：
year: 27
Daphne: 270
CLeo: 273.346
- 第五题
#include <iostream>
#include <string>
const int year = 12;
int main() {
int month[year];
// 使用char* 和 string 两种方法初始化
const char* money[year] = {
"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
};
std::string money_str[year] = {
"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
};
// 基于范围的for循环
for(int &x: month)
std::cin >> x;
for(int i=0;i<year;i++)
{
std::cout << money[i] << "销量为：" << month[i] << std::endl;
std::cout << money_str[i] << "销量为：" << month[i] << std::endl;
}
return 0;
}
运行结果：
1
2
3
4
5
6
7
8
9
10
11
12
January销量为：1
January销量为：1
February销量为：2
February销量为：2
March销量为：3
March销量为：3
April销量为：4
April销量为：4
May销量为：5
May销量为：5
June销量为：6
June销量为：6
July销量为：7
July销量为：7
August销量为：8
August销量为：8
September销量为：9
September销量为：9
October销量为：10
October销量为：10
November销量为：11
November销量为：11
December销量为：12
December销量为：12
- 第六题
#include <iostream>
#include <string>
const int pre_year = 12;
const int all_year = 3;
int main() {
int month[all_year][pre_year];
int year[all_year] = {0};
int all = 0;
// 使用char* 和 string 两种方法初始化
const char* money[pre_year] = {
"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
};
std::string money_str[pre_year] = {
"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"
};
for(int i=0;i<all_year;i++)
{
for(int j=0;j<pre_year;j++)
{
std::cin >> month[i][j];
year[i] += month[i][j];
}
all += year[i];
}
for(int i=0;i<all_year;i++)
{
std::cout << "第" << (i+1) << "年销量为：" << year[i] << std::endl;
}
std::cout << "总销量为：" << all << std::endl;
return 0;
}
运行结果：
三年都是一样的值，数太多不放上去了。
9
10
11
12
第1年销量为：78
第2年销量为：78
第3年销量为：78
总销量为：234
- 第七题
由于geline会将换行符当作空字符串，因此在使用getline之前如果有数字或其他的输入将会产生换行符，因此需要使用cin.get()这种不带参数的方法去读取达到过滤的作用。
#include <iostream>
#include <string>
struct car
{
std::string product;
int year;
};
int main() {
int cars;
std::cout << "How many cars do you wish to catalog?";
std::cin >> cars;
std::cin.get(); // 捕捉换行符
car *all_car = new car [cars];
for(int i=0;i<cars;i++)
{
std::cout << "Car #" << (i+1) << ":" <<std::endl;
std::cout << "Please enter the make:";
getline(std::cin, all_car[i].product);
std::cout << "Please enter the year made:";
std::cin >> all_car[i].year;
std::cin.get(); // 捕捉换行符
}
std::cout << "Here is your collection:" <<std::endl;
for(int i=0;i<cars;i++)
{
std::cout << all_car[i].year << " " << all_car[i].product << std::endl;
}
delete [] all_car;
return 0;
}
运行结果：
How many cars do you wish to catalog?2
Car #1:
Please enter the make:Hudson Hornet
Please enter the year made:1952
Car #2:
Please enter the make:Kaiser
Please enter the year made:1951
Here is your collection:
1952 Hudson Hornet
1951 Kaiser
- 第八题
对c风格字符串进行比较使用strcmp，相同返回0，不同返回1
#include <iostream>
#include <cstring>
int main() {
char word[10];
int num = 0;
std::cout << "Enter words (to stop, type the word done):" << std::endl;
std::cin >> word;
while (strcmp(word, "done"))
{
num += 1;
std::cin >> word;
}
std::cout << "You entered a total of " << num << " words." << std::endl;
return 0;
}
运行结果：
Enter words (to stop, type the word done):
anteater birthday category dumpster
envy finagle geometry done for sure
You entered a total of 7 words.
- 第九题
对于string使用关系表达式比较
#include <iostream>
#include <string>
int main() {
std::string word;
int num = 0;
std::cout << "Enter words (to stop, type the word done):" << std::endl;
std::cin >> word;
while (word != "done")
{
num += 1;
std::cin >> word;
}
std::cout << "You entered a total of " << num << " words." << std::endl;
return 0;
}
运行结果：
Enter words (to stop, type the word done):
anteater birthday category dumpster
envy finagle geometry done for sure
You entered a total of 7 words.
- 第十题
#include <iostream>
int main() {
int num_star;
std::cout << "Enter number of rows:";
std::cin >> num_star;
for(int i=0;i<num_star;i++)
{
for(int j=0;j<(num_star-i-1);j++)
{
std::cout << ".";
}
for(int k=0;k<(i+1);k++)
{
std::cout << "*";
}
std::cout << std::endl;
}
return 0;
}
运行结果：
Enter number of rows:5
....*
...**
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