小学生四则运算练习系统（C++实现）

//420128040112xxx //完成日期：2022/05/09 //小学生四则运算练习系统 #include <iostream> #include <stdlib.h> #include <time.h> using namespace std; int Add(); //声明加法函数 int Sub(); //声明减法函数 int Mul(); //声明乘法函数 int Div(); //声明除法函数 void eval(int right); //声明评价函数 int main() //主菜单 { int c; while(1) { cout << "============================" << endl; cout << "1.加法\t\t2.减法\n" << endl; cout << "3.乘法\t\t4.除法\n" << endl; cout << "0.退出" << endl; cout << "============================" << endl; cout << "请选择：" << endl; cin >> c; if(!c) break; //c为0程序直接结束 switch(c) //能一直循环，除非c为0 { case 1:Add(); break;//c为1选择加法运算 case 2:Sub(); break;//c为2选择减法运算 case 3:Mul(); break;//c为3选择乘法运算 case 4:Div(); break;//c为4选择除法运算 } } } int Add() //加法运算 { int x,y,answer,right = 0; //right是做对的题目数 srand(time(NULL)); //与rand()函数配套使用 for(int i = 0; i < 10; i++) { x = rand()%10 + 1; //rand()函数产生的是伪随机数，是按照公式算出来的 y = rand()%10 + 1; //生成1到10的随机数 cout << x << " + " << y << " = "; cin >> answer; if(answer == (x + y)) right++; } eval(right); //调用评价函数 } int Sub() //减法运算 { int x,y,answer,right = 0; srand(time(NULL)); for(int i = 0; i < 10; i++) { x = rand()%10 + 1; y = rand()%10 + 1; if(x > y) //确保x与y相减的结果是正数 { cout << x << " - " << y << " = "; cin >> answer; if(answer == (x - y)) right++; } else { cout << y << " - " << x << " = "; cin >> answer; if(answer == (y - x)) right++; } } eval(right); } int Mul() //乘法运算 { int x,y,answer,right = 0; srand(time(NULL)); for(int i = 0; i < 10; i++) { x = rand()%10 + 1; y = rand()%10 + 1; cout << x << " * " << y << " = "; cin >> answer; if(answer == (x * y)) right++; } eval(right); } int Div() //除法运算 { int x,y,answer,right = 0; srand(time(NULL)); for(int i = 0; i < 10; i++) { x = rand()%9 + 1; //生成1到9的随机数 y = rand()%9 + 1; cout << x*y << " ÷ " << y << " = "; //为了可以整除 cin >> answer; if(answer == x)//因为是（x*y）÷y，所以只要比较answer和x是否相等即可 right++; } eval(right); } void eval(int right) //评价 { right = right * 10; //得到总分 if(right == 100) cout << "你好厉害哇，优秀！\n"; else if((right == 80) || (right == 90)) cout << "很不错啦，良好！\n"; else if((right == 60) || (right == 70)) cout << "你合格了!\n"; else cout << "你怎么没及格啊，要再接再厉呀！加油！\n"; }