C++实现四则混合运算计算器

本文实例为大家分享了C++实现四则混合运算的计算器，供大家参考，具体内容如下

计算器是带括号的四则运算实际上利用的是栈后进先出的原则

转换思想：

#define _CRT_SECURE_NO_WARNINGS 1
#include"stdio.h"
#include"stdlib.h"
#include"string.h"
#define maxsize 1024
typedef struct
{
 float data[maxsize];
 int top;
}Stack1;
void Initstack1(Stack1 *S)
{
 S = (Stack1*)malloc(sizeof(Stack1));
 S->top = -1;
}
int Push1(Stack1 *S, float ch)
{
 if (S->top == maxsize - 1)
  return 0;
 else
 {
  S->top++;
  S->data[S->top] = ch;
  return 1;
 }
}//入栈Push
int Pop1(Stack1 *S, float ch)
{
 if (S->top == -1)
  printf("栈上溢出!\n");
 else
  ch = S->data[S->top];
 S->top--;
 return 1;
}//出栈
typedef struct
{
 char data[maxsize];
 int top;
}Stack2;
void Initstack2(Stack2 *S)
{
 S = (Stack2*)malloc(sizeof(Stack2));
 S->top = -1;
}
int Push2(Stack2 *S, char ch)
{
 if (S->top == maxsize - 1)
  return 0;
 else
 {
  S->top++;
  S->data[S->top] = ch;
  return 1;
 }
}//入栈Push
int Pop2(Stack2 *S, char ch)
{
 if (S->top == -1)
  printf("栈上溢出!\n");
 else
  ch = S->data[S->top];
 S->top--;
 return 1;
}//出栈
int Comop(char ch) //判断是否是运算符
{
 switch (ch)
 {
 case'+':
 case'-':
 case'*':
 case'/':
 case'(':
 case')':
 case'#':
  return 1;
 default:
  return 0;
 }
}//判断ch是否为运算符
char Prior[7][7] =
{ // 运算符优先级表
   // '+' '-' '*' '/' '(' ')' '#'
 /*'+'*/{ '>', '>', '<', '<', '<', '>', '>' },
 /*'-'*/{ '>', '>', '<', '<', '<', '>', '>' },
 /*'*'*/{ '>', '>', '>', '>', '<', '>', '>' },
 /*'/'*/{ '>', '>', '>', '>', '<', '>', '>' },
 /*'('*/{ '<', '<', '<', '<', '<', '=', '< ' },
 /*')'*/{ '>', '>', '>', '>', ' ', '>', '>' },
 /*'#'*/{ '<', '<', '<', '<', '<', '> ', '=' },
};
int Opid(char op1)
{
 switch (op1)
 {
 case'+':return 0;
 case'-':return 1;
 case'*':return 2;
 case'/':return 3;
 case'(':return 4;
 case')':return 5;
 case'#':return 6;
 default:return -123456;
 }
}
char Precede(char op1, char op2) //优先级比较
{
 int a, b;
 a = Opid(op1); b = Opid(op2);
 return(Prior[a][b]);
}
float Operation(float a, char op, float b)
{
 switch (op)
 {
 case '+':
  return b + a;
 case '-':
  return b - a;
 case '*':
  return b * a;
 case '/':
  return b / a;
 default:
  return -123456;
 }
}
void CreateExpression(char *exp)
{

 if (exp == NULL)
 {
  exit(1);
 }
 scanf("%s", exp);
}
void TransmitExpression(char *exp, char postexp[]) //中缀表达式转换后缀表达式
{
 Stack2 FZ;
 Initstack2(&FZ);
 int i = 0;
 char x;
 FZ.top = -1;
 Push2(&FZ, '#');
 FZ.data[FZ.top] = '#';
 while (*exp != '\0')
 {
  if (!Comop(*exp))
  {
   while (*exp >= '0'&&*exp <= '9')//读取一个数字串
   {
    postexp[i++] = *exp;
    exp++;
   }
   postexp[i++] = '#';
  }
  else
   switch (Precede(FZ.data[FZ.top], *exp))
  {
   case'<':
    Push2(&FZ, *exp);
    exp++;
    break;
   case'=':
    x = FZ.data[FZ.top];
    Pop2(&FZ, x);
    exp++;
    break;
   case'>':
    postexp[i++] = FZ.data[FZ.top];
    x = FZ.data[FZ.top];
    Pop2(&FZ, x);
    break;
  }
 }
 while (FZ.data[FZ.top] != '#')
 {
  postexp[i++] = FZ.data[FZ.top];
  x = FZ.data[FZ.top];
  Pop2(&FZ, x);
 }
 postexp[i] = '\0';
}
float EvaluateExpression(char *postexp) //后缀表达式的计算
{
 Stack1 SZ;
 Initstack1(&SZ);
 float a, b, d;
 SZ.top = -1;
 while (*postexp != '\0')
 {
  switch (*postexp)
  {
  case'+':
  case'-':
  case'*':
  case'/':
   a = SZ.data[SZ.top];
   Pop1(&SZ, a);
   b = SZ.data[SZ.top];
   Pop1(&SZ, b);
   Push1(&SZ, Operation(a, *postexp, b));
   break;
  default:
   d = 0;
   while (*postexp >= '0'&&*postexp <= '9')
   {
    d = 10 * d + *postexp - '0';
    postexp++;
   }
   Push1(&SZ, d);
   SZ.data[SZ.top] = d;

   break;
  }
  postexp++;
 }
 return(SZ.data[SZ.top]);
}
int Error(char *exp) //错误表达式判断
{
 int i = 0;
 while (exp[i] != '\0')
 {
  if (
   ((exp[i] == '+' || exp[i] == '-' || exp[i] == '*' || exp[i] == '/') && (exp[i + 1] == ')'))
   || ((exp[i] == '+' || exp[i] == '-' || exp[i] == '*' || exp[i] == '/') && (exp[i - 1] == '('))
   || (exp[i] == ')'&&exp[i + 1] == '(')
   || (exp[i] == '('&&exp[i + 1] == ')')
   || ((exp[i] == ')') && exp[i + 1] >= '0'&&exp[i + 1] <= '9')
   || (exp[i] >= '0'&&exp[i] <= '9'&&exp[i + 1] == '(')
   || (exp[0] == '+' || exp[0] == '-' || exp[0] == '*' || exp[0] == '/' || exp[0] == ')')
   || ((exp[i] == '+' || exp[i] == '-' || exp[i] == '*' || exp[i] == '/') && (exp[i + 1] == '+' || exp[i + 1] == '-' || exp[i + 1] == '*' || exp[i + 1] == '/'))
   || (exp[i] == '/'&&exp[i + 1] == '0')
   )
   return 1;
  else
  if (exp[i] == '\0')
   return 0;
  i++;
 }
 return 0;
}
void menu()
{
 printf("\t\t--------------------------------------------\n");
 printf("\t\t|     计算器     |\n");
 printf("\t\t|    ----------------   |\n");
 printf("\t\t|    |    |   |\n");
 printf("\t\t|    ----------------   |\n");
 printf("\t\t|    1 2 3 +    |\n");
 printf("\t\t|    4 5 6 -    |\n");
 printf("\t\t|    7 8 9 *    |\n");
 printf("\t\t|    0 （ ） /    |\n");
 printf("\t\t--------------------------------------------\n");
 printf("\t\t 请输入你要进行的操作：\n");
 printf("\t\t a表达式求值 b清空 c退出\n");
}
void clear()
{
 system("cls");
 menu();
}
void Quit()
{
 system("cls");
 exit(1);
}
void main()
{
 char c;
 char exp[maxsize];
 char postexp[maxsize] = { 0 };
 menu();
 while (1)
 {
  scanf("%c", &c);
  switch (c)
  {
  case 'a':
  sr :
   printf("请输入要计算的表达式:\n");
   CreateExpression(exp);
   if (!Error(exp))
   {
    TransmitExpression(exp, postexp);
    printf("后缀表达式为：%s\n", postexp);
    printf("表达式结果为：%s=", exp);
    printf("%g\n", EvaluateExpression(postexp));
    break;
   }
   else
   if (Error(exp))
   {
    printf("您输入的表达式有误！\n");
    goto sr;//goto语句在循环体里进行跳转
   }
  case'b':
   clear();
   break;
  case'c':
   Quit();
   break;
  }
 }
 system("pause");
}

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