第一单元
练习 1.1
编写程序,在标准输出上打印Hello, World。
#include <iostream>
int main(int argc, const char * argv[]) {
std::cout << "Hello, ceshi!\n";
return 0;
}
练习 1.2
我们编写程序使用乘法运算符*,来打印两个数的积。
#include <iostream>
int main(int argc, const char * argv[]) {
int a,b;
std::cout<<"请输入两个数字:\n";
std::cin>>a>>b;
std::cout << "数字 " << a << " and " << b
<< " 乘积是 " << a * b << std::endl;
return 0;
}
练习 1.3
我们将所有的输出操作放在一条很长的语句中,重写程序,将每个运算对象的打印操作放在一条独立的语句中。
#include <iostream>
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;
}
练习 1.4
合法的注释语句
#include <iostream>
int main(int argc, const char * argv[]) {
std::cout << "/*";
std::cout << "*/";
std::cout << /* "*/" */";
std::cout << /* "*/" /* "/*" */;
return 0;
}
练习 1.5
使用while循环将50到100整数相加
#include <iostream>
int main(int argc, const char * argv[]) {
int sum = 0, val = 50;
while (val <= 100){
sum += val;
val += 1;
}
std::cout << "Sum of 50 to 100 inclusive is "
<< sum << std::endl;
return 0;
}
练习 1.6
使用 for 循环将50到100整数相加
#include <iostream>
int main(int argc, const char * argv[]) {
int sum = 0, val = 50;
for(;val<=100;val++){
sum += val;
}
std::cout << "Sum of 50 to 100 inclusive is "
<< sum << std::endl;
return 0;
}
练习 1.7
编写程序,从cin读取一组数,输出其和
#include <iostream>
int main(int argc, const char * argv[]) {
int sum = 0, val;
for (int i=1;i<=10;i++){
std::cout<< "请输入第" << i << "个数:"<<std::endl;
std::cin>>val;
sum += val;
}
std::cout << "输入的10个数字之和是:"
<< sum << std::endl;
return 0;
}
练习 1.8
打印一个范围内的数),使其能处理用户输入的第一个数比第二个数小的情况
#include <iostream>
int main()
{
int s = 0, e = 0;
std::cout << "请输入两个数字: ";
std::cin >> s >> e;
if (s <= e) {
while (s <= e){
std::cout << s << " ";
++s;
}
std::cout << std::endl;
}
else{
std::cout << "输入不合法!!!";
}
}