C语言数据结构之简易计算器
更新时间:2017年11月01日 10:03:30 作者:thj19980720
这篇文章主要为大家详细介绍了C语言数据结构之简易计算器,文中示例代码介绍的非常详细,具有一定的参考价值,感兴趣的小伙伴们可以参考一下
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; }
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