> #include<math.h>
> #include<stdio.h>
> void main()
> {int i;
> float mon[13],m=0.00,n;
> printf("input  the balances of the twelve months\n");
> for(i=1;i<13;i++)
> {
> scanf("%f",&mon[i]);
> printf("%f\n",mon[i]);//这个不用的.
> m=m+mon[i];
> }
> n=m/12;
> printf(" %f",n);//这里没有空格吧?后面加个回车...
> }