支持多位数，括号，四则运算，的计算器算法c++实现
#include<iostream>
#include<string>
#include<stack>
#include<stdio.h>
using namespace std;
//23+(34*45)/(5+6+7)
//2+3*5+6+7
int priority(char c)
{
if (c == ')')
{
return 4;
}
else if (c == '^')
{
return 3;
}
else if (c == '*' || c == '/' || c == '%')
{
return 2;
}
else if (c == '+' || c == '-')
{
return 1;
}
else if (c == '(')
{
return 0;
}
else
{
cout << "不符合要求的字符!" << endl;
return -1;
}
} //返回字符c的优先级
bool isNumber(char c)
{
if (c >= '0'&& c <= '9')
{
return true;
}
else
{
return false;
}
}
bool isOperator(char c)
{
if (c == '+' || c == '-' || c == '*' || c == '/' || c == '%')
{
return true;
}
else
{
return false;
}
}
bool isBracket(char c)
{
if (c == '(' || c == ')')
{
return true;
}
else
{
return false;
}
}
double charToDouble(char c)
{
return (double)(c - '0');
}
double stringToDouble(string s)
{
return atof(s.c_str());
}
int stringToInt(string s)
{
return atoi(s.c_str());
}
char doubleToChar(double d)
{
return (char)(d + 48);
}
string doubleToString(double d)
{
return to_string(d);
}
double charBasicCalculate(char left, char op, char right)
{
if (isNumber(left) && isNumber(right))
{
if (op == '+')
{
return (charToDouble(left) + charToDouble(right));
}
else if (op == '-')
{
return (charToDouble(left) - charToDouble(right));
}
else if (op == '*')
{
return (charToDouble(left) * charToDouble(right));
}
else if (op == '/')
{
return (charToDouble(left) / charToDouble(right));
}
else if (op == '%')
{
return (left - '0') % (right - '0');
}
else
{
cout << "操作符错误!";
return -1;
}
}
else
{
cout << "错误运算参数";
return -1;
}
}//返回double 的基本计算函数
double doubleBasicCalculate(double left, char op, double right)
{
if (op == '+')
{
return left + right;
}
else if (op == '-')
{
return left - right;
}
else if (op == '*')
{
return left*right;
}
else if (op == '/')
{
return left / right;
}
else if (op == '%')
{
return (int)left % (int)right;
}
else
{
cout << "操作符错误!";
return -1;
}
}
double stringBasicCalculate(string left, char op, string right)
{
if (op == '+')
{
return (stringToDouble(left) + stringToDouble(right));
}
else if (op == '-')
{
return (stringToDouble(left) - stringToDouble(right));
}
else if (op == '*')
{
return (stringToDouble(left) * stringToDouble(right));
}
else if (op == '/')
{
return (stringToDouble(left) / stringToDouble(right));
}
else if (op == '%')
{
return (stringToInt(left)) % (stringToInt(right));
}
else
{
cout << "操作符错误!";
return -1;
}
}
bool isExpression(const char* expression)//判断表达式是否合法
{
int i = 0;
int leftBracket=0;//记录左括号个数
int rightBracket=0;//记录右括号个数
while (expression[i] != '\0')
{
if (expression[i] == ' ')
{
cout << "不要输入空格!";
return false;
}
if (i == 0 && !(isNumber(expression[i]) || isBracket(expression[i])))//第一个元素不是数字或者左括号
{
cout << "异常1";
return false;
}
if (!(isNumber(expression[i]) || isOperator(expression[i]) || isBracket(expression[i])))//其它符合要求的字符
{
cout << "异常2";
return false;
}
if (i != 0 && isOperator(expression[i - 1]) && (isOperator(expression[i]) || expression[i] == ')'))//操作符后还是操作符或右括号不合法
{
cout << "异常3";
return false;
}
if (i!=0 && expression[i-1] == '(' && !isNumber(expression[i]))//左括号右边不是数字debug2(i-1误写i)
{
cout << "异常4";
return false;
}
else
{
if (expression[i] == '(')
leftBracket++;
if (expression[i] == ')')
rightBracket++;
}
i++;//debug1添加上i++;
}
if (leftBracket == rightBracket)
{
return true;//表达式合理
}
else
{
cout << "异常5";
return false;
}
}
string dealBasicChar(char c, int n)//c表示位上的字符，n表示位级别,234,中c=2时n=2,c=3时，n=1,c=4时，n=0每个字符拆成0-9内
{
string temp;
temp.append(1,c);
for (int i = 0; i < n; i++)
{
temp.append("*(9+1)");
}
/*cout << "dealBasicChar" << temp << endl;*/
return temp;
}
string dealBasicString(string s)
{
string temp;
temp.append("(");
int size = s.size();
for (int i = 0;i
{
temp.append(dealBasicChar(s.at(i), size - i - 1));
if (i != size - 1)//不是最后,添加"+";
{
temp.append("+");
}
}
temp.append(")");
/*cout << "dealBasciString" << temp << endl;*/
return temp;
}
string dealExpression(const char* expression)//化为0-9以内的表达式：23+12：（9+1+9+1+3）+（9+1+2）
{
string temp = expression;
string temp2;
string texpression;
int i=0;
while(i
{
if (i!=temp.size()-1 && isNumber(temp.at(i)) && isNumber(temp.at(i+1)))//探测是否是多位数//debug当i=temp.size()-1时调用temp.at(i+1)发生越界，加上条件，i!=temp.size()-1,当i=temp.size()-1时由&&的处理原则,前面不成立不会执行后面条件.
{
/*cout << i<
int j;
for ( j = 0; isNumber(temp.at(i + j)); j++)
{
temp2.append(1,temp.at(i+j));//获得多位数存储在temp2中
}
texpression.append(dealBasicString(temp2));//转化为标准表达式并加入texpression中。
temp2.clear();//debug1:temp2为归零导致错误.
/*cout << texpression << endl;*/
i = i + j ;
}
else
{
texpression.append(1,temp.at(i));
i++;
}
}
/*cout << texpression<
return texpression;
}
double infixCalculate(const char* expression)//直接计算中缀表达式debug1括号括号优先级设置出错 OK
{
stack opStack;
stack nuStack;
for (int i = 0; expression[i] != '\0'; i++)
{
if (isNumber(expression[i]))
{
cout << "isNumber" << endl;
nuStack.push(string(1,expression[i]));//转化为string
}
else if (isOperator(expression[i]))
{
cout << "isOperator" << endl;
if (opStack.empty())//栈为空直接将操作符压入
{
cout << "empty()" << endl;
opStack.push(expression[i]);
}
else//区分优先级
{
cout << "not empty()" << endl;
if (priority(opStack.top()) < priority(expression[i]))
{
cout << "priority" << endl;
opStack.push(expression[i]);
}
else
{
cout << "not priority" << endl;
char op=opStack.top();//stack.top返回顶端元素不删除,stack.pop无返回值只删除顶端元素
opStack.pop();
string left = nuStack.top();
nuStack.pop();
string right = nuStack.top();
nuStack.pop();
nuStack.push(doubleToString(stringBasicCalculate(left, op, right)));
opStack.push(expression[i]);
}
}
}
else if (expression[i] == '(')
{
cout << "左括号" << endl;
opStack.push(expression[i]);
}
else if (expression[i] == ')')
{
cout << "右括号" << endl;
while (1)
{
if (opStack.top() == '(')
{
opStack.pop();//弹出左括号结束
break;
}
else
{
char op = opStack.top();
opStack.pop();
string left = nuStack.top();
nuStack.pop();
string right = nuStack.top();
nuStack.pop();
nuStack.push(doubleToString(stringBasicCalculate(left, op, right)));
}
}
}
else
{
cout << "符号错误！" << endl;
}
}
while (1)//计算剩余操作符
{
if (opStack.empty())
{
break;
}
else
{
char op = opStack.top();
opStack.pop();
string left = nuStack.top();
nuStack.pop();
string right = nuStack.top();
nuStack.pop();
nuStack.push(doubleToString(stringBasicCalculate(left, op, right)));
}
}
return stringToDouble(nuStack.top());
}
double postfixCalculate(const char* expression)
{
stack nuStack;
for (int i = 0; expression[i] != '\0'; i++)
{
if (isNumber(expression[i]))
{
nuStack.push(string(1, expression[i]));
}
else if (isOperator(expression[i]))
{
char op = expression[i];
string left = nuStack.top();
nuStack.pop();
string right = nuStack.top();
nuStack.pop();
nuStack.push(doubleToString(stringBasicCalculate(left, op, right)));
}
else
{
cout << "符号错误!" << endl;
}
}
return stringToDouble(nuStack.top());
}
string infixTranPostfix(const char* expressionIn)
{
stack opStack;
string temp;
for (int i = 0; expressionIn[i] != '\0'; i++)
{
if (isNumber(expressionIn[i]))
{
temp.append(1, expressionIn[i]);
}
else if (isOperator(expressionIn[i]))
{
if (opStack.empty())
{
opStack.push(expressionIn[i]);
}
else
{
if (priority(opStack.top()) < priority(expressionIn[i]))
{
opStack.push(expressionIn[i]);
}
else
{
temp.append(1, opStack.top());
opStack.pop();
opStack.push(expressionIn[i]);
}
}
}
else if (expressionIn[i] == '(')
{
opStack.push(expressionIn[i]);
}
else if (expressionIn[i] == ')')
{
while (1)
{
if (opStack.top() == '(')
{
opStack.pop();
break;
}
else
{
temp.append(1, opStack.top());
opStack.pop();
}
}
}
else
{
cout << "符号错误!";
}
}
while (1)
{
if (opStack.empty())
{
break;
}
else
{
temp.append(1, opStack.top());
opStack.pop();
}
}
return temp;
}
double calculate1(const char* expression)
{
if (isExpression(expression))
{
string tExpression = dealExpression(expression);
string ttExpression = infixTranPostfix(tExpression.c_str());
return postfixCalculate(ttExpression.c_str());
}
else
{
cout << "表达式错误!" << endl;
}
}
double calculate2(const char* expression)
{
if (isExpression(expression))
{
string s = dealExpression(expression);
return infixCalculate(s.c_str());
}
else
{
cout << "表达式错误!" << endl;
}
}
int main()
{
cout << "输入一个表达式:" << endl;
string expression;
cin >> expression;
cout << "计算结果为:" << endl;
cout << calculate2(expression.c_str())<
/*cout << "请输入表达式:" << endl;
string expression;
cin >> expression;
cout << "计算结果为:" << endl;
cout << calculate(expression.c_str())<
/*cout << "测试6：postfixCalculate" << endl; OK
string s1 = "1+2+2*3+4+(1+2*3)";
cout << infixTranPostfix(s1.c_str());*/
//5 测试 infixCalculate OK
//4 测试deal expression() Ok
/*string expression;
cin >> expression;
cout << dealExpression(expression);*/
/*char* expression;
double result;
cout << "输入表达式：" << endl;
cin >> expression;*/
//1 测试isNumber(),isOperator(),isBracket() OK
//char c;
//cin >> c;
//if (isNumber(c))
//cout << "数字";
//else if (isOperator(c))
//cout << "操作符";
//else if (isBracket(c))
//cout << "括号";
//else
//cout << "其它字符";
//2 测试isExpression() OK
//char expression[100];
//cin >> expression;
//if (isExpression(expression))
//cout << "是表达式" << endl;
//else
//cout << "不是表达式" << endl;
//3 测试basicCalculat() OK
/*cout << basicCalculate('3', '%', '5');*/
/*int a = toascii('s');
int b = 's' - '0'+48;
cout << a << endl << b << endl;*/
}
