第 二 章      C++简单程序设计
2-10 执行完下列语句后，a、b、c三个变量的值为多少？
a = 30;
b = a++;
c = ++a;
解：
a：32 ； b：30 ； c：32；
2-13 写一条for语句，计数条件为n从100到200，步长为2；然后用while和do…while语句完成同样的循环。
解：
for循环：
for (int n = 100; n <= 200; n += 2);
while循环：
int x = 100;
while (n <= 200)
n += 2;
do…while循环：
int n = 100;
do
{
n += 2;
} while(n <= 200);
2-17 修改下面这个程序中的错误，改正后它的运行结果是什么？
#include <>
void main()
int i
int j;
i = 10; /* 给i赋值
j = 20; /* 给j赋值 */
cout << "i + j = << i + j; /* 输出结果 */
return 0;
}
解：
改正：
#include <>
int main()
{
int i;
int j;
i = 10; n";
cout << "You are: " << yourAge << " years old\n";
myAge++; .\n";
cout << "I am: " << myAge << " years old.\n";
明解c语言cout << "You are: " << yourAge << " years old\n";
cout << "Another year passes\n";
cout << "I am: " << myAge++ << " years old.\n";
cout << "You are: " << ++yourAge << " years old\n";
cout << "Let's print it again.\n";