C实验代码.rar

1#include<iostream> #include<cmath> using namespace std; int main() {double a,b,c,s,area; cout<<"please input a,b,c:"; cin>>a>>b>>c; if(a+b<=c) cerr<<"a+b<=c,error!"<<endl; else if(b+c<=a) cerr<<"b+c<=a,error!"<<endl; else if(c+a<=b) cerr<<"c+a<=b,error!"<<endl; else {s=(a+b+c)/2; area=sqrt(s*(s-a)*(s-b)*(s-c)); cout<<"area="<<area<<endl;} return 0; } 2（1）#include<iostream> #include<iomanip> using namespace std; int main() {float a[5]; cout<<"input data:"; for(int i=0;i<5;i++) cin>>a[i]; cout<<setiosflags(ios::fixed)<<setprecision(2); for(int i=0;i<5;i++) cout<<setw(10)<<a[i]<<endl; return 0; } （2）#include<iostream> using namespace std; int main() {float a[5]; int i; cout<<"input data:"; for(i=0;i<5;i++) cin>>a[i]; cout.setf(ios::fixed) ; cout.precision(2); for(i=0;i<5;i++) {cout.width(10); cout<<a[i]<<endl;} return 0; } 3#include<iostream> #include<fstream> using namespace std; void fun1() {int a[10]; ofstream outfile1("f1.dat"),outfile2("f2.dat"); if(!outfile1) {cerr<<"open f1.dat error!"<<endl; exit(1); } if(!outfile2) {cerr<<"open f2.dat error!"<<endl; exit(1); } cout<<"enter 10 integer numbers:"<<endl; for (int i=0;i<10;i++) {cin>>a[i]; outfile1<<a[i]<<" ";} cout<<"enter 10 integer numbers:"<<endl; for(int i=0;i<10;i++) {cin>>a[i]; outfile2<<a[i]<<" ";} outfile1.close(); outfile2.close(); } void fun2() {ifstream infile("f1.dat"); if(!infile) {cerr<<"open f1.dat error!"<<endl; exit(1); } ofstream outfile ("f2.dat",ios::app); if(!outfile) {cerr<<"open f2.dat 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.dat"); if(!infile) {cerr<<"open f2.dat error!"<<endl; exit(1); } int a[20]; int i,j,t; for(i=0;i<20;i++) infile>>a[i]; for(i=0;i<19;i++) for(j=0;j<19-i;j++) if(a[j]>a[j+1]) {t=a[j];a[j]=a[j+1];a[j+1]=t;} infile.close(); ofstream outfile("f2.dat",ios::out); if(!outfile) {cerr<<"open f2.dat error!"<<endl; exit(1);} cout<<"data in f2.dat:"<<endl; for(i=0;i<20;i++) {outfile<<a[i]<<" "; cout<<a[i]<<" ";} cout<<endl; outfile.close(); } int main() {fun1(); fun2(); fun3(); return 0; } 4#include<iostream> #include<fstream> using namespace std; struct staff { int num; char name[20]; int age; double pay; }; int main() { staff staf[7] = { 2101,"Li",34,1203, 2104,"Wang",23,674.5, 2108,"Fun",54,778, 3006,"Xue",45,476.5, 5101,"Ling",39,656.6 }, staf1; ofstream outfile1("staff.dat"); if (!outfile1) cerr << "open staff.dat error!" << endl; exit(1); } ofstream outfile("staff.dat", ios::out); fstream iofile("staff.dat", ios::in | ios::out | ios::binary); if (!iofile) { cerr << "open error!" << endl; abort(); } int i, m, num; cout << "Five staff:" << endl; for (i = 0; i < 5; i++) { cout << staf[i].num << " " << staf[i].name << " " << staf[i].age << " " << staf[i].pay << endl; iofile.write((char*)&staf[i], sizeof(staf[i])); } cout << "please input 2 staff data you want to insert:" << endl; iofile.seekp(0, ios::end); for (i = 0; i < 2; i++) { cin >> staf1.num >> staf1.name >> staf1.age >> staf1.pay; iofile.write((char*)&staf1, sizeof(staf1)); } cout << "Seven staff:" << endl; iofile.seekg(0, ios::beg); for (i = 0; i < 7; i++) { iofile.read((char*)&staf[i], sizeof(staf[i])); cout << staf[i].num << " " << staf[i].name << " " << staf[i].age << " " << staf[i].pay << endl; } bool find; cout << "enter number you want search,enter 0 to stop."; cin >> num; while (num) { find = false; iofile.seekg(0, ios::beg);//ios::beg 从开头开始 for (i = 0; i < 7; i++) { iofile.read((char*)&staf[i], sizeof(staf[i])); if (num == staf[i].num) { m = iofile.tellg(); cout << num << " is No." << m / sizeof(staf1) << endl; cout << staf[i].num << " " << staf[i].name << " " << staf[i].age << " " << staf[i].pay << endl; find = true; break; } } if (!find) cout << "not found the stuff" << endl; cout << "enter number you want search,enter 0 to stop."; cin >> num; } iofile.close(); return 0; }