C语言编程:编写函数分别完成求和、求平均值及求高于平均值的数据及个...答:int sum(int a[],int n){int i,sum;for(i=0,sum=0;i<n;i++)sum+=a[i];return sum;}double average(int a[],int n){int i,sum;for(i=0,sum=0;i<n;i++)sum+=a[i];return 1.0*sum/n;}int over_avg(int a[],int n, double avg){int i,count;for(i=0,count=0...