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脚本之家。

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