c++数组里如何把里面的加号原样输出

Question

cout<<+'<<endl
cout<<数组【1】也不显示

输出结果不显示
将中缀转换前缀

#include <iostream>
using namespace std;
#define maxsize 50
int getPriority(char a)
{
    if (a == '/' && a == '*')
        return 1;
    else
        return 0;
    
}
void infixToPostFix(char infix[], char s2[], int &top2)
{
    char s1[maxsize];int top1=-1;
    int i = 0;
    while(infix[i] != '\0')
    {
        if('0'<=infix[i] && infix[i] <='9')
        {
            s2[++top2] = infix[i];
            ++i;
        }
        else if(infix[i] == '(')
        {
            s1[++top1]=infix[i];
            ++i;
            
        }
        else if(infix[i] == '+' || infix[i] == '/' || infix[i] == '-' || infix[i] == '*')
        {
            if(top1 == -1 || s1[top1] == '(' || getPriority(infix[i]) > getPriority(s1[top1]))
            {
                s1[++top1]==infix[i];
                ++i;    
            }
            else
            {
                s2[++top2] == s1[top1--];
            }
        }
        else if(infix[i] == ')')
        {
            while(s1[top1] != '(' )
                s2[++top2] =s1[top1--];
            --top1;
            ++i;    
        }
    }
    while(top1 != -1)
    {
        s2[++top2] == s1[top1--];
    }
}
int main()
{
    char infix[maxsize]={'1','+','2','-','4','*','(','4','+','3',')','+','9'};//前缀数学式
    char infix2[maxsize];
    int top2=-1;
    infixToPostFix(infix, infix2, top2);
    for(int i=-1;i<=top2;++i)
    {
        cout<<infix[i];   
    }
    cout<<endl;
    for(int i=-1;i<=top2;++i)
    {
        cout<<infix2[i];   
    }
    return 0;
}

Answer 1

cout<<"+"<<endl;