第一个程序 #include using namespace std; int main () { float a, b, sum; cout << "请输入加数a："; cin >> a; cout << "请输入加数b："; cin >> b; cout << "\n请输入结果\na+b="; cin >> sum; if (sum == (a+b)) cout << "Right!\n" << endl; else cout << "Not correct! Try again!" << endl; return 0; } 第二个程序 #include using namespace std; int main () { float a, b, sum; bool flag = false; cout << "请输入加数a："; cin >> a; cout << "请输入加数b："; cin >> b; while (!flag) { cout << "\n请输入结果\na+b="; cin >> sum; if (sum == (a+b)) { flag = true; cout << "Right!\n" << endl; } else { cout << "Not correct! Try again!" << endl; } } return 0; } 第三个程序 #include using namespace std; int main () { float a, b, sum; int i = 0; bool flag = false; cout << "请输入加数a："; cin >> a; cout << "请输入加数b："; cin >> b; while (!flag && (i < 3)) { cout << "\n请输入结果\na+b="; cin >> sum; if (sum == (a+b)) { flag = true; cout << "Right!\n" << endl; } else { cout << "Not correct! Try again!" << endl; } i++; } if (i == 3) { cout << "Not correct! You have tried three times! Test over!" << endl << endl; } return 0; } 第四个程序 #include #include #include using namespace std; int main () { float a, b, sum, count = 0, score = 0; int i = 0; srand ((unsigned)time (NULL)); //产生随机数种子 while (i < 10) { //a+(int)(n*rand()/(RAND_MAX+1.0))产生一个a到n之间的随机数 a = 1 + (int) (10 * rand () / (RAND_MAX + 1)); b = 1 + (int) (10 * rand () / (RAND_MAX + 1)); cout << "\n请输入结果\n" << a << "+" << b << "="; cin >> sum; if (sum == (a+b)) { score += 10; cout << "Right!\n" << endl; } else { count++; cout << "Not correct! Try again!" << endl; } i++; } cout << "得分：" << score << "\t\t做错了" << count << "道题" << endl; return 0; } 用C++语言写的，均已通过测试，欢迎采纳……
