文档介绍：第二章 C++简单程序设计
解：
int yourAge = 39;
2-10执行完下列语句后， a b、c三个
源程序：
cout << "I am: " << myAge << " years
变量的值为多少？
#include <>
old.\n";
a = 30;
int main()
cout << "You are: " << yourAge << " years
b = a++;
{
old\n";
c = ++a;
int i;
myAge++; // postfix increment
a： 32 ； b: 30 ； c： 32；
cout << "请输入一个数字：";
++yourAge; // prefix increment
2-13写一条for语句，计数条件为n从
cin >> i;
cout << "One year passes...\n";
100到200,步长为2;然后用while和
cout << "您输入一个数字是 "<< i << endl;
cout << "I am: " << myAge << " years
do…while语句完成同样的循环。
return 0;
old.\n";
解：
}
cout << "You are: " << yourAge << " years
for循环：
程序运行输出：
old\n";
for (int n = 100; n <= 200; n += 2);
2-20打印ASC1码为32~127的字符。
cout << "Another year passes\n";
while循环：
#include <>
cout << "I am: " << myAge++ << " years
int x = 100;
int main()
old.\n";
while (n <= 200)
{
cout << "You are: " << ++yourAge << "
n += 2;
for (int i = 32; i<128; i++)
years old\n";
do…while循环：
cout << (char) i;
cout << "Let's print it again.\n";
int n = 100;
return 0;
cout << "I am: " << myAge << " years
do
}
old.\n";
{
程序运行输出：
cout << "You are: " << yourAge << " years
n += 2;
!"#$%G'()*+，./0123456789:;<>?***@ABCDE
old\n";
} while(n <= 200);
FGHIJKLMNOP_QRSTUVWXYZ[\]A'abcdefg
return 0;
2-17修改下面这个程序中的错误，改正
hijklmnopqrstuvwxyz<|>〜s
}
后它的运行结果是什么？
2-21运行下面的程序，观察其输出，与
解：
#include <>
你的设想是否