求指导，这段程序哪里出有关问题了

求指导，这段程序哪里出问题了

C/C++ code

#include<stdio.h>#include<stdlib.h>int sw(char *a){    int i=0,c=0;    while(a[i]){        if(a[i]>='0'&&a[i]<='9')            c=c*10+a[i]-'0';            i++;    }    if(a[0]=='-')        c=-c;    return c;}int main(){    char a[99],b[99];    int a1,b1,c;    while(scanf("%s %s",a,b)!=EOF){        a1=sw(a);        b1=sw(b);    }    c=a1+b1;    printf("%d\n",c);    return 0;}

C/C++ code

    while(scanf("%s %s",a,b)==2){//这儿改下吧        a1=sw(a);        b1=sw(b);    }