C语言数据结构之简易计算器

本文实例为大家分享了C语言简易计算器的具体代码，供大家参考，具体内容如下

主要解决了处理负数、小数等的基础运算操作，无图形界面

#include <iostream>
#include <stack>
using namespace std;

class Calculator{
private:
 int Priority(char fuhao);
 double CalSuffix(string PostfixExp);

public:
 double Calculate(string InfixExp);

 string InfixToSuffix(string InfixExp);

};

double Calculator::CalSuffix(string PostfixExp){
 double tmpresult,ch1,ch2;
 double tmpnum,tmpxiaoshu=1;
 int i=0,tmpdashu;
 int isfu=0; ///
 stack<double> stk2;
 while(PostfixExp[i]!='\0'){
 isfu=0; ///
 if(PostfixExp[i]>=48&&PostfixExp[i]<=57){
  if(PostfixExp[i-1]=='-'){ /////
  isfu=1;
  }
  tmpxiaoshu=1;
  tmpdashu=10;
  tmpnum = PostfixExp[i]-48;
  while(PostfixExp[++i]>=48&&PostfixExp[i]<=57){
  tmpnum = tmpnum*tmpdashu+ (PostfixExp[i]-48);
  }
  i=i-1;
  if(PostfixExp[++i]=='.'){
  while(PostfixExp[++i]>=48&&PostfixExp[i]<=57){
   tmpxiaoshu=tmpxiaoshu*0.1;
   tmpnum = tmpnum + (PostfixExp[i]-48)*tmpxiaoshu;
  }
  i=i-1;
  }
  else{
  i=i-1;
  }
  if(isfu){ ////
  tmpnum=tmpnum*(-1);
  }
  stk2.push(tmpnum);
 }

 else if(PostfixExp[i]=='&'||PostfixExp[i]==' '){
 }

 else {
  if(PostfixExp[++i]>=48&&PostfixExp[i]<=57){
  i=i-1;
  }
  else {
  i=i-1;
  ch2 = stk2.top();
  stk2.pop();
  ch1 = stk2.top();
  stk2.pop();
  switch(PostfixExp[i]){
   case '+': tmpnum = ch1 + ch2; break;
   case '-': tmpnum = ch1 - ch2; break;
   case '*': tmpnum = ch1 * ch2; break;
   case '/': tmpnum = ch1 / ch2;
   if(ch2==0) cout<<"除数为零";break;
  }
  stk2.push(tmpnum);
  }
 }
 i++;
 }
 if(stk2.empty()!=1){
 tmpresult = stk2.top();
 stk2.pop();
 }
 return tmpresult;
}

double Calculator::Calculate(string InfixExp){
 double result;
 result = CalSuffix(InfixToSuffix(InfixExp));
 return result;
}

int Calculator::Priority(char fuhao){
 switch(fuhao){
 case '+':
 case '-': return 2;
 case '*':
 case '/': return 3;
 case '(':
 case ')': return 1;
 default:
  return 0;
 }
}
string Calculator::InfixToSuffix(string InfixExp){
 stack<char> stk;
 string PostfixExp = "   ";
 int i=0,j=0;
 char tmpfuhao;
 int flag = 0; //判断多位数的头数是否为零
 while(InfixExp[i]!='\0'){
 if(InfixExp[i]>=48&&InfixExp[i]<=57){
  flag = 0;
  PostfixExp[j++]='&';
  PostfixExp[j++]=InfixExp[i];
  if(InfixExp[i]=='0'){
  flag = 1;
  }
  while(InfixExp[++i]>=48&&InfixExp[i]<=57){
  if(flag==0)
   PostfixExp[j++]=InfixExp[i];
  else
   cout<<"输入错误数字";
  }
  i=i-1;
  if(InfixExp[++i]=='.'){
  PostfixExp[j++]='.';
  while(InfixExp[++i]>=48&&InfixExp[i]<=57){
   PostfixExp[j++]=InfixExp[i];
  }
  i=i-1;
  }
  else{
  i=i-1;
  }
 }

 else if(InfixExp[i]=='('){
  stk.push(InfixExp[i]);
 }

 else if(InfixExp[i]==')'){
  if(stk.empty()){
  cout<<"表达式错误！";
  }
  else{
  tmpfuhao = stk.top();
  while(tmpfuhao!='('){
   if(stk.empty()){
   cout<<"表达式错误!";
   }
   else{
   PostfixExp[j++] = '&';
   PostfixExp[j++] = tmpfuhao;
   stk.pop();
   tmpfuhao = stk.top();
   }
  }
  stk.pop();
  }
 }

 else if(InfixExp[i]=='+'||InfixExp[i]=='-'||InfixExp[i]=='*'||InfixExp[i]=='/'){
  if(i==0||((InfixExp[--i]<48||InfixExp[i]>57)&&InfixExp[i]!=')')){
  i++;
  PostfixExp[j++]='&';
  PostfixExp[j++]='-';
  while(InfixExp[++i]>=48&&InfixExp[i]<=57){
   PostfixExp[j++]=InfixExp[i];
  }
  i=i-1;
  if(InfixExp[++i]=='.'){
   PostfixExp[j++]='.';
   while(InfixExp[++i]>=48&&InfixExp[i]<=57){
   PostfixExp[j++]=InfixExp[i];
   }
   i=i-1;
  }
  else{
   i=i-1;
  }
  }
  else{
  i++;
  if(stk.empty()){
  stk.push(InfixExp[i]);
  }
  else{
  tmpfuhao = stk.top();
  if(Priority(tmpfuhao)<Priority(InfixExp[i])){
   stk.push(InfixExp[i]);
  }
  else{
   while(Priority(tmpfuhao)>=Priority(InfixExp[i])){
   PostfixExp[j++] = '&';
   PostfixExp[j++] = tmpfuhao;
   stk.pop();
   if(stk.empty()!=1){
    tmpfuhao = stk.top();
   }
   else break;
   }
   stk.push(InfixExp[i]);
  }
  }
  }
 }
 else{
  cout<<"符号错误！";
  break;
 }
 i++;
 }

 while(!stk.empty()){
 tmpfuhao = stk.top();
 PostfixExp[j++] = '&';
 PostfixExp[j++] = tmpfuhao;
 stk.pop();
 }
 PostfixExp[j++] = '\0';
 return PostfixExp;
}

int main(int argc, const char * argv[]) {
 string a;
 Calculator a1;
 cin>>a;
 cout<<a1.Calculate(a)<<endl;
 cout<<a1.InfixToSuffix(a);
 return 0;
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。

原文链接：http://blog.csdn.net/thj19980720/article/details/78378154