#include<iostream>
#include<string.h>
int result(int len,char * str)
{
    int result=0;
    char * fuhao=new char [len];
    int * shuzi=new int [len];
    memset (fuhao,0,sizeof(char )*len);
    memset (shuzi,0,sizeof(int )*len);
    int shuzitop=-1;
    int fuhaotop=-1;
    for(int i=0;i<len;i++)
    {
        if('0'<=str[i]<='9')
            shuzi[++shuzitop]=str[i]-'0';
        if(str[i]=='-'||str[i]=='+'||str[i]=='*'||str[i]=='/')
        {
                if(str[i]=='*')
                {
                    int num1=shuzi[shuzitop];
                    int num2=str[++i];
                    num1*=num2;
                    shuzi[shuzitop]=num1;
            
                }
                if(str[i]=='/')
                {
                    int num1=shuzi[shuzitop];
                    int num2=str[++i];
                    num1/=num2;
                    shuzi[shuzitop]=num1;
                }
                else
                    fuhao[++fuhaotop]=str[i];   
        }
    }
    while(fuhaotop!=-1)
    {
        int a=shuzi[shuzitop--];
        int b=shuzi[shuzitop];//此处报错了
        if(fuhao[fuhaotop--]=='+')
        {
            b+=a;
            shuzi[shuzitop]=b;
        }
        if(fuhao[fuhaotop--]=='-')
        {
            b+=a;
            shuzi[shuzitop]=b;
        }
    }
    result=shuzi[shuzitop];
    delete [] shuzi;
    delete [] fuhao;
    return  result;
}
void main()
{
    char *a="1+2";
    printf("the result is :%d ",result(5,a));
}

可能 有些多 大家慢慢看  求解释

昨天晚上到现在 还没明白  

。。。

if('0'<=str[i]<='9')没有这样比较的吧！数学中可以，计算机不这样吧！你有什么问题，或者不懂的，可以直接问，你是程序不懂，还是怎么滴

嗯嗯  那个是我着急 那样写的 我感觉  int b=shuzi[shuzitop];//此处报错了这步 为什么报错 我这代码我都读了好几遍了才贴出来的

  printf("the result is :%d ",result(5,a));
//这个错误 不是 我调的时候忘改了

好吧  大神求带啊  可怜下我被  。。。