.1声明及定义 #include <iostream.h> long sum(void){ int m,n,S=0; cout<<"Please input:" for (cin>>n,m=1;m<=n;m++) s+=m; cout<<\nSum="<<s; return s; long x=sum();/开工函数初始化x调用sum ■ void main(void){}//空函数有运行结果2.1 声明及定义 „ #include <iostream.h> „ long sum(void){ „ int m, n, s=0; „ cout<<"Please input:"; „ for(cin>>n,m=1; m<=n; m++) s+=m; „ cout<<"\nSum="<<s; „ return s; „ } „ long x=sum( );//开工函数初始化x调用sum „ void main(void){ } //空函数有运行结果