CB-question/Infix Using stack at master · Anmoldube/CB-question · GitHub

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import java.util.Stack;
public class infix {
public static void main(String[] args) {
            String str = "9-5+3*4/6";
           Stack<Integer> val = new Stack<>();
           Stack<Character> op = new Stack<>();
           for (int i = 0; i < str.length(); i++) {
                char ch  = str.charAt(i);
                int ascii = (int)ch;
                if(ascii >= 48 && ascii <= 57){
                    val.push(ascii-48);
                }
                else if (op.size()==0) {
                    op.push(ch);
                }
                else {
                    if(ch == '+' || ch == '-'){
                        int v2 = val.pop();
                        int v1 = val.pop();
                        if(op.peek() == '-') val.push(v1-v2);
                        if(op.peek() == '+') val.push(v1+v2);
                        if(op.peek() == '*') val.push(v1*v2);
                        if(op.peek() == '/') val.push(v1/v2);
                        op.pop();
                        op.push(ch);
                    }
                    if(ch == '*' || ch == '/'){
                        if(op.peek()=='*' || op.peek() == '/'){
                        int v2 = val.pop();
                        int v1 = val.pop();
                        if(op.peek() == '*') val.push(v1*v2);
                        if(op.peek() == '/') val.push(v1/v2);
                        op.pop();
                        op.push(ch);
                        }
                        else op.push(ch);
                    }
                }
           }
           while (val.size()>1) {
                int v2 = val.pop();
                int v1 = val.pop();
                if(op.peek() == '-') val.push(v1-v2);
                        if(op.peek() == '+') val.push(v1+v2);
                        if(op.peek() == '*') val.push(v1*v2);
                        if(op.peek() == '/') val.push(v1/v2);
                        op.pop();
                        // op.push(ch);
           }
           System.out.println(val);
    }
}