//program 5.8 using a nested loop to generate multplication tables

include<iostream>

include<iomanip>

include<cctype>

using namespace std;

int main() {
int table = 0;
const int table_min = 2;
const int table_max = 12;
char ch = 0;

do
{
    cout << endl << "what size would you like (" << table_min << "to" << table_max << " )？";
    cin >> table;
    cout << endl;

    //make sure table size is within the limits
    if (table<table_min || table>table_max) {
        cout << "invalid table size entered. program terminated." << endl;
        exit(1);//返回0表示正常结束；返回1表示非正常结束
    }

    //create the top line of the table
    cout << "     |";
    for (int i = 1; i <= table; i++) cout << "" << setw(3) << i << " |";
    cout << endl;

    //create the separatorrow
    for (int i = 1; i <= table; i++)cout << "-----";
    cout << endl;

    for (int i = 0; i <= table; i++) {
        cout << "" << setw(3) << i << "  |";

        //output the values in a row
        for (int j = 1; j <= table; j++)cout << "" << setw(3) << i*j << " |";
        cout << endl;
    }

    //check if another table is required
    cout << endl << "do you want another table(y or n)?";
    cin >> ch;
    cout << endl;
} while (tolower(ch) == 'y');

return 0;

}