function.java

带括号计算器的Java源代码在NetBeans中的实现

/*
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 * and open the template in the editor.
 */

package Calculator;

/**
 *
 * @author wxyc
 */
class function{
String input,output;
double num[];
char symbol[];
int i,j,t,symbolI,numI;
public function(String s1)
{
input = s1+"#";
num = new double[50];
symbol = new char[50];
i = 0;
j = 0;
t=0;
numI = 0;
symbolI = 0;
symbol[0] = '#';
num[0] = 0;
}
public String calculate()
{
while(i<input.length()){
    if(input.charAt(i)=='('){
        t++;
    }
    if(input.charAt(i)==')'){
        t--;
    }
    i++;
}
if(t!=0){
    return "INPUT ERROR!";
}
i=0;
while(i<input.length())
{
if(!ThisIsSymbol(input.charAt(i)))
{
if((input.charAt(i)<'0'||input.charAt(i)>'9')&&input.charAt(i)!='.')
return "INPUT ERROR!";
j=i;
while(input.charAt(i)>='0'&&input.charAt(i)<='9'||input.charAt(i)=='.'){
i++;
}
numI++;
num[numI] = Double.parseDouble(input.substring(j,i));
if(j>=2&&input.charAt(j-1)=='-'&&input.charAt(j-2)=='('){
num[numI]=-1*num[numI];
}
}
else{
if(compareLv(symbol[symbolI],input.charAt(i)) == -1){
if(i>=1&&input.charAt(i)=='-'&&input.charAt(i-1)=='('){
 i++;
}else{
    symbolI++;
    symbol[symbolI] = input.charAt(i);
    i++;
}
}
else if(compareLv(symbol[symbolI],input.charAt(i)) == 0){
i++;
symbolI--;
}
else while(compareLv(symbol[symbolI],input.charAt(i)) == 1){
if(input.charAt(i)=='-'&&input.charAt(i-1)=='*'){
    i++;
    num[numI]=-1*num[numI];
}else if(input.charAt(i)=='-'&&input.charAt(i-1)=='+'){
    i++;
    symbol[symbolI]='-';
}else if(input.charAt(i)=='-'&&input.charAt(i-1)=='-'){
    i++;
    symbol[symbolI]='+';
}else{
num[numI-1] = counter(num[numI-1],symbol[symbolI],num[numI]);
numI--;
symbolI--;
}
}
}
}
if(numI==1) num[0] = num[1];
return String.valueOf(num[0]);
}
public int compareLv(char c1,char c2) {
int x,y;
x = symbolLv(c1);
y = symbolLv(c2);
if(x==0&&y==0) return 0;
if(x==1&&y==4) return 0;
else if(y==4) return 1;
else if(y==1) return -1;
else if(x>y||x==y) return 1;
else return -1;
}
public int symbolLv(char c){
switch(c){
case '#': return 0;
case '(': return 1;
case '+': return 2;
case '-': return 2;
case '*': return 3;
case '/': return 3;
case ')': return 4;
}
return 5;
}
public boolean ThisIsSymbol(char c){
if(c =='+'||c=='-'||c =='*'||c =='/'||c =='('||c ==')'||c =='#')
return true;
return false;
}
public double counter(double c1,char o,double c2){
if(o == '+') return c1+c2;
else if(o == '-') return c1-c2;
else if(o == '*') return c1*c2;
else return c1/c2;
}
}