7-4

#include <iostream>#include <fstream>using namespace std;void fun1(){ int a[10]; ofstream outfile1("f1.data",ios::out),outfile2("f2.data",ios::out); if(!outfile1) {  cerr<<"open error!"<<endl;  exit(1); } if(!outfile2) {  cerr<<"open error!"<<endl;  exit(1); } cout<<"input 10 integer numbers:"<<endl; for(int i=0;i<10;i++) {  cin>>a[i];  outfile1<<a[i]<<" "; } cout<<"input 10 integer numbers:"<<endl; for(i=0;i<10;i++) {  cin>>a[i];  outfile2<<a[i]<<" "; } outfile1.close(); outfile2.close();}void fun2(){ ifstream infile("f1.data"); if(!infile) {cerr<<"open error!"<<endl;    exit(1); } ofstream outfile("f2.data",ios::app); if(!outfile) {    cerr<<"open error!"<<endl;exit(1); } int a; for(int i=0;i<10;i++) {  infile>>a;  outfile<<a<<" "; } infile.close(); outfile.close();}void fun3(){ ifstream infile("f2.data"); if(!infile) {  cerr<<"open error!"<<endl;  exit(1); } int a[20]; int i,j,t; for(i=0;i<20;i++) infile>>a[i]; for(i=0;i<20;i++) for(j=i+1;j<20;j++) if(a[i]>a[j]) {t=a[i];a[i]=a[j];a[j]=t;} infile.close(); ofstream outfile("f2.data",ios::out); if(!outfile) {   cerr<<"open error!"<<endl;   exit(1); } cout<<"data in f2.data:"<<endl; for(i=0;i<20;i++) {  outfile<<a[i]<<" ";  cout<<a[i]<<" "; } cout<<endl; outfile.close();}int main(){ fun1(); fun2(); fun3(); return 0;}