#include <stdio.h>
#include <string.h>

char    stack[100];
int        top = 0;

void push(char ch);
char pop(void);

int    main(void)
{
    int        i,n;
    char    str[100];
    puts("Please input the expression");
    gets(str);
    n = strlen(str);
    for(i = 0; i < n; i++)
    {
        if(str[i] == '(')
            continue;
        else if(str[i] >= '0' && str[i] <= '9')
            putchar(str[i]);
        else if((str[i] == '+') || (str[i] == '-') || (str[i] == '*'))
            push(str[i]);
        else if(str[i] == ')')
            putchar(pop());
    }
    return    0;
}
void push(char    ch)
{
    stack[top++] = ch;
}
char pop(void)
{
    return    stack[--top];
}

[此贴子已经被作者于2022-6-1 00:54编辑过]