计算器

#include<stdio.h>  
#include<string.h>  
#include<stdlib.h>  
  
#define MAXCHAR 256  
  
void stringFilter(const char* pInputStr , long lInputLen , char* pOutputStr)  
{  
    bool hash[26] = {0};    //统计字符是否出现  
    int i , j;  
    for(i = 0 , j = 0 ; i < lInputLen; ++i)  
    {  
        if(false == hash[pInputStr[i] - ‘a‘])     //该字符还木有出现过  
        {  
            hash[pInputStr[i] - ‘a‘] = true;  
            pOutputStr[j++] = pInputStr[i];  
        }  
    }  
    pOutputStr[j] = ‘\0‘;  
}  
  
void stringZip(const char* pInputStr , long lInputLen , char* pOutputStr)  
{  
    int i , j , k , num;  
    char buffer[20];  
    for(i = 0 , k = 0; i < lInputLen; )  
    {  
        num = 0;  
        for(j = i + 1 ; j < lInputLen ; ++j)  
        {  
            if(pInputStr[i] == pInputStr[j])     //统计字符串中每个字符后面连续出现的重复字母次数  
                ++num;  
            else  
                break;  
        }//for  
        if(0 != num)    //num可能是两位或三位或更多位的整数  
        {  
            memset(buffer , 0 , sizeof(buffer));  
            itoa(num + 1 , buffer , 10);      //将整数按10进制转换为字符串  
            strcpy(pOutputStr + k , buffer);  
            k += strlen(buffer);  
        }  
        pOutputStr[k++] = pInputStr[i];  
        i = i + num + 1;  
    }//for  
    pOutputStr[k] = ‘\0‘;  
}  
  
void arithmetic(const char* pInputStr , long lInputLen , char* pOutputStr)  
{  
    int i , j , num1 , num2 , result , num_space;  
    char buffer[4];  
    bool add , sub;  
    add = sub = false;  
    for(i = 0 , num_space = 0 ; i < lInputLen ; ++i)  
    {  
        if(pInputStr[i] == ‘ ‘)  
            ++num_space;  
    }  
    if(2 != num_space)     //空格数非法  
    {  
        pOutputStr[0] = ‘0‘;  
        pOutputStr[1] = ‘\0‘;  
        return ;  
    }  
    num1 = num2 = 0;  
    for(i = 0 ; pInputStr[i] != ‘ ‘ ; ++i)  
    {  
        if(pInputStr[i] >= ‘0‘ && pInputStr[i] <= ‘9‘)  
            num1 = num1 * 10 + pInputStr[i] - ‘0‘;  
        else                 //第一个操作数中有非法字符  
        {  
            pOutputStr[0] = ‘0‘;  
            pOutputStr[1] = ‘\0‘;  
            return ;  
        }  
    }  
    for(j = i + 1 ; pInputStr[j] != ‘ ‘ ; ++j);  
    if(1 != j - i - 1)     //运算符长度不合法  
    {  
        pOutputStr[0] = ‘0‘;  
        pOutputStr[1] = ‘\0‘;  
        return ;  
    }  
    else    //操作符的长度为1  
    {  
        if(‘+‘ != pInputStr[i+1] && ‘-‘ != pInputStr[i+1])    //操作符号非法  
        {  
            pOutputStr[0] = ‘0‘;  
            pOutputStr[1] = ‘\0‘;  
            return ;  
        }  
        else  
        {  
            if(‘+‘ == pInputStr[i+1])  
                add = true;  
            if(‘-‘ == pInputStr[i+1])  
                sub = true;  
            for(i = j + 1 ; i < lInputLen ; ++i)  
            {  
                if(pInputStr[i] >= ‘0‘ && pInputStr[i] <= ‘9‘)  
                    num2 = num2 * 10 + pInputStr[i] - ‘0‘;  
                else          //第二个操作数中有非法字符  
                {  
                    pOutputStr[0] = ‘0‘;  
                    pOutputStr[1] = ‘\0‘;  
                    return ;  
                }  
            }//for  
            if(add)  
                result = num1 + num2;  
            else if(sub)  
                result = num1 - num2;  
            memset(buffer , 0 , sizeof(buffer));  
            itoa(result , buffer , 10);      //将整数按10进制转换为字符串  
            strcpy(pOutputStr , buffer);  
        }//esle  
    }//else  
}  
  
  
int main(void)  
{  
    printf(" -- 2014年华为校园招聘机试题 (http://blog.csdn.net/hackbuteer1) --\n\n");  
    char pInputStr1[] = {"aaabbbcccdde"};  
    char pInputStr2[] = {"aaaaaaaaaaaabbcddddddddddddddddde"};  
    char pInputStr3[] = {"3 + 4"};  
    char pOutputStr1[MAXCHAR] = {0};  
    char pOutputStr2[MAXCHAR] = {0};  
    char pOutputStr3[MAXCHAR] = {0};  
    stringFilter(pInputStr1 , strlen(pInputStr1) , pOutputStr1);  
    stringZip(pInputStr2 , strlen(pInputStr2) , pOutputStr2);  
    arithmetic(pInputStr3 , strlen(pInputStr3) , pOutputStr3);  
    puts(pOutputStr1);  
    puts(pOutputStr2);  
    puts(pOutputStr3);  
    return 0;  
}