1001 A+B Format （20 分）

Calculate a+b and output the sum in standard format -- that is, the digits must be separated into groups of three by commas (unless there are less than four digits).

Input Specification:

Each input file contains one test case. Each case contains a pair of integers a and b where −10​6​​≤a,b≤10​6​​. The numbers are separated by a space.

Output Specification:

For each test case, you should output the sum of a and b in one line. The sum must be written in the standard format.

Sample Input:

-1000000 9

Sample Output:

-999,991 两种思路，第一种是今天写的，将结果预处理好存在字符串里直接输出

1 #include
       
         2 #include
        
          3 #include
         
           4 using namespace std; 5 int main() 6 { 7     long long a,b,c; 8     char s[100]; 9     while(scanf("%lld%lld",&a,&b)!=EOF)10     {11         c=a+b;12         int flag=0;13         if(c<0)14         {15             flag=1;16             c=0-c;17         }18         int l=0;19         int g,w=0;20         while(c)21         {22             g=c%10;23             c/=10;24             s[l++]=g+'0';25             w++;26             if(w%3==0)s[l++]=',';27         }28         if(a+b==0)cout << "0" <
          
           =0;i--)34                 cout << s[i];35             cout <
          
         
        
       

 

另一种是去年写的，一边输出一边加逗号，翻看以前的代码被自己秀到了。。。

1 #include
       
         2 #include
        
          3 #include
         
           4 using namespace std; 5 int main() 6 { 7     int a,b,c,d=1; 8     while(scanf("%d%d",&a,&b)!=EOF) 9     {10         a+=b;11         c=0;12         d=1;13         if(a<0){printf("-"); a=0-a;}14         b=a;15         while(a/=10)16         {17             c++;18             d*=10;19         }20         c++;21         for(;c>0;)22         {23             printf("%d",b/d);24             b%=d;25             d/=10;26             c--;27             if(!(c%3)&&c)printf(",");28         }29         printf("\n");30     }31     return 0;32 }