AAA.rar_visual c

#include <stdio.h> #include <ctype.h> #include <stdlib.h> double eval(double a, double b, char c) { double r; switch(c) { case '+': r = a + b; break; case '-': r = a - b; break; case '*': r = a * b; break; case '/': r = a / b; break; } return r; } void menu() { printf("\t\t\t简单计算机\n\n"); printf("1)一般数据算术\t\t2)单运算符表达式计算\t\t3)退出\n"); printf("C)清屏\t\t\tR)显示此菜单\n"); printf("请选择:>"); } void docal(int n) { double b; static double r; char c; if(n == 2) { r = 0; return; } printf("请输入数据, 清屏退出模式:>"); while(1) { c = getchar(); if(toupper(c) == 'C') return; else ungetc(c, stdin); if(n == 0) scanf("%c%lf", &c, &b); else scanf("%lf%c%lf", &r, &c, &b); while(getchar() != '\n'); r = eval(r, b, c); if((int)r == r) printf("%.0f\n", r); else printf("%.3f\n", r); } } void calc() { double a, b, r; char c; r = 0; menu(); while(1) { c = getchar(); while(getchar() != '\n'); switch(c) { case '1': docal(0); ungetc('c', stdin); break; case '2': docal(1); ungetc('c', stdin); break; case '3': return; case 'c': case 'C': docal(2); system("cls"); menu(); break; case 'r': case 'R': menu(); break; default: printf("输入有误!\n"); } } } int main() { calc(); return 0; }