I need help to follow this algorithm to my code

Question

The algorithm is:
if operator: while the stack is not empty, pop all operators as long as they are of equal or higher precedence and the top is not '('. Concatenate each operator from stack to postfix. Then push the current operator
if (c == '+' || c == '-' || c == '/' || c == '%' || c == '*'){
                    while (stack.empty() == false){
                         if (c == '*' && stack.peek() != '(')
                              postfix += stack.pop();
                         if (c == '/' && stack.peek() != '(' && stack.peek() != '*')
                              postfix += stack.pop();
                         if (c == '%' && stack.peek() != '(' && stack.peek() != '*' && stack.peek() != '/')
                              postfix += stack.pop();
                         if (c == '+' && stack.peek() != '(' && stack.peek() != '*' && stack.peek() != '/' && stack.peek() != '%' )
                              postfix += stack.pop();
                         if (c == '-' && stack.peek() != '(' && stack.peek() != '*' && stack.peek() != '/' && stack.peek() != '%' )
                              postfix += stack.pop();
               stack.push(c);

Answer 1

this is my revision, but still I don't know how it doesn't work when I test my program..can someone tell me where I failed??
if (c == '+' || c == '-' || c == '/' || c == '%' || c == '*'){
                    while (stack.empty() == false && stack.peek() != '('){
                         if (stack.peek() == '*' || c == '*')
                              postfix += stack.pop();
                         else if (stack.peek() == '/' && (c == '+' || c == '-' || c =='%' || c == '/'))
                              postfix += stack.pop();
                         else if (stack.peek() == '%' && (c == '+' || c == '-' || c =='%'))
                              postfix += stack.pop();
                         else if (stack.peek() == '+' && (c == '+' || c == '-'))
                                   postfix += stack.pop();
                         else if (stack.peek() == '-' && c == '-')
                              postfix += stack.pop();
               stack.push(c);
               }