PTA 九宫格输入法

#include <stdlib.h>
#include <cstdio>
#include <iostream>
#include <queue>
#include <stack>
#include <string.h>
#include <math.h>
#include <algorithm>

#define mem(t, v)   memset ((t) , v, sizeof(t))
#define INF 0x3f3f3f3f

using namespace std;

char g[10][10]={"1,.?!","2ABC","3DEF","4GHI","5JKL","6MNO","7PQRS","8TUV","9WXYZ","0 "};
char input[550];


int main(){
    gets(input);

    char output[500]="";
    int top=0;
    int len=strlen(input);
    for(int i=0;i<len;){
        if(input[i]>='0'&&input[i]<='9'){
            int cnt=0,num;
            while(input[i]>='0'&&input[i]<='9'){
                num=input[i++]-'0';
                cnt++;
            }
            output[top++]=g[num-1][cnt-1];
        }
        else i++;
    }
    for(int i=0;i<top;i++)
        printf("%c",output[i]);
    printf("\n");
    return 0;
}