编译错误？？？

Kerwin__17 @ 2016-10-22 16:17:14

#include<iostream>
#include<cstring>
using namespace std;
char a[20] ;
bool fu = 0 ;
int l; 
int main( ){
    gets(a);
    l=strlen(a);
    if(a[0]=='-')
        cout<<'-';
    for(int i=l;i>=0;i--)
    {
        if(a[i]>='1'&&a[i]<='9'){
            cout<<a[i];
        }
    }
    return 0;
}

by Kerwin__17 @ 2016-10-22 17:41:52

这个程序是个半残，加上需要cstdio库，兼职不能看

by Kerwin__17 @ 2016-10-22 17:42:30

已经AC

#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
char b[200],a[200];
int l,head=0;
int main() {
    int temp=0;
    gets(b);
    l=strlen(b);
    for(int i=l; i>=0; i--) {
        if(b[0]=='-'&&temp==0) {
            a[head++]='-';
            temp=1;
        }
        if(b[i]>='0'&&b[i]<='9')
            a[head++]=b[i];
    }
    for(int i=0; i<=l; i++) {
        if(a[i]=='-')
            continue;
        if(a[i]=='0')
            a[i]=0;
        if(a[i+1]!='0')
            break;
    }
    if(a[0]=='-')
        cout<<'-';
    for(int i=0; i<=head; i++)
        if(a[i]>='0'&&a[i]<='9')
            cout<<a[i];
    return 0;
}