1759 加减表达式

#include<cstdio>
#include<cstring>
using namespace std;
char s[1001];
int l,ans,sum,t=1;
int main()
{
    int i,j;
    scanf("%s",&s);
    l=strlen(s);
    i=0;
    L:while(s[i]==‘+‘||s[i]==‘-‘)
    {
        if(s[i]==‘-‘)
          t*=-1;
        i++;
    }
    sum=0;
    while(s[i]<=‘9‘&&s[i]>=‘0‘)
      sum=sum*10+s[i]-‘0‘,i++;
    ans=ans+t*sum;
    t=1;
    if(i<l)
      goto L;
    printf("%s=%d",s,ans);
    return 0;
}