示例1
#include <iostream>
#include <cstdlib>
#include <sstream>
#include <string>
#include <cctype>
using namespace std;
using std::string;
void cinTest1() {
int ival;
// read cin and test only for EOF; loop is executed even if there are other IO failures
while (cin >> ival, !cin.eof()) {
//{
cout << "now:" << cin.rdstate() << endl;
cout << "data =>" << ival << endl;
if (cin.bad()) // input stream is corrupted; bail out
throw runtime_error("IO stream corrupted");
if (cin.fail()) { // bad input
cerr<< "bad data" << endl; // warn the user
//cin.clear(istream::failbit); // reset the stream
//cin.ignore();
cin.clear();
cout << "ok:" << cin.rdstate() << endl;
continue; // get next input
}
// ok to process ival
}
}
void cinTest2() {
int ival;
string line;
string word;
while (getline(cin, line)) {
istringstream lstream(line);
while (lstream >> word) {
if (!isdigit(word[0])) {
cerr<< "bad data: " << word << endl;
continue;
} else {
istringstream wstream(word);
wstream >> ival;
}
} // while small
} // while large
}
int main() {
cinTest2();
return 0;
}
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示例2
文件1：functions.cpp
#include <vector>
using std::vector;
void reset(const int *ip) {
//*ip = 0; // changes the value of the object to which ip points
ip = 0;
}
// 交換
void swap(int &v1, int &v2) {
int tmp = 0;
tmp = v1;
v1 = v2;
v2 = tmp;
}
// returns an iterator that refers to the first occurrence of value
// the reference parameter occurs contains a second return value
vector<int>::const_iterator find_val(
vector<int>::const_iterator beg, // first element
vector<int>::const_iterator end, // one past last element
int value, // the value we want
vector<int>::size_type &occurs
) // number of times it occurs
{
// res_iter will hold first occurrence, if any
vector<int>::const_iterator res_iter = end;
occurs = 0; // set occurrence count parameter
for ( ; beg != end; ++beg)
if (*beg == value) {
// remember first occurrence of value
if (res_iter == end)
res_iter = beg;
++occurs; // increment occurrence count
}
return res_iter; // count returned implicitly in occurs
}
文件2：Sales_item.h
#ifndef SALES_ITEM_H
#define SALES_ITEM_H
#include <string>
using namespace std;
class Sales_item {
public:
Sales_item(): units_sold(10), revenue(500.0) { }
double avg_price() const;
bool same_isbn(const Sales_item &rhs) const
{ return isbn == rhs.isbn; }
private:
string isbn;
unsigned units_sold;
double revenue;
};
#endif
文件3：Sales_item.cpp
#include "Sales_item.h"
double Sales_item::avg_price() const {
if (units_sold) {
return revenue/units_sold;
} else {
return 0;
}
}
文件4：test.cpp
#include <iostream>
#include <cstdlib>
#include <vector>
#include "Sales_item.h"
using std::vector;
using namespace std;
extern void reset(const int *);
extern void swap(int &, int &);
extern vector<int>::const_iterator find_val(
vector<int>::const_iterator, // first element
vector<int>::const_iterator, // one past last element
int, // the value we want
vector<int>::size_type &);
void showCinSts() {
cout << cin.rdstate() << endl;
if (cin.bad()) {
cout << "bad" << endl;
}
if (cin.fail()) {
cout << "fail" << endl;
}
if (cin.eof()) {
cout << "eof" << endl;
}
if (cin.good()) {
cout << "good" << endl;
}
}
void test() {
const int value = 1;
const int *p = &value;
cout << "値:" << *p << endl;
reset(p);
cout << "値:" << *p << endl;
p = NULL;
int i = 10;
int j = 20;
cout << "値i:" << i << '/t' << "値j:" << j << endl;
swap(i, j);
cout << "値i:" << i << '/t' << "値j:" << j << endl;
vector<int> ivec;
vector<int>::const_iterator it;
vector<int>::size_type ctr = 0;
int word = 0;
cout << "Input the numbers for the vactor:" << endl;
while (cin >> word) {
cout << word << endl;
ivec.push_back(word); // append word to text
}
//cout << cin.eof() << endl;
/*
ivec.push_back(1);
ivec.push_back(2);
ivec.push_back(3);
*/
istream::iostate old_state = cin.rdstate();
showCinSts();
cin.clear();
//fflush(stdin);
//cin.sync();
//cin.setstate(istream::eofbit);
//cin.clear(istream::failbit);
//cin.clear(istream::eofbit);
showCinSts();
//cout << cin.eof() << endl;
int find = 0;
cout << "Input a number to search:" << endl;
cin >> find;
cin.setstate(old_state);
cout << cin.rdstate() << endl;
typedef vector<int>::const_iterator (*fndVal)(
vector<int>::const_iterator, // first element
vector<int>::const_iterator, // one past last element
int, // the value we want
vector<int>::size_type &);
fndVal pF = find_val;
it = (*pF)(ivec.begin(), ivec.end(), find, ctr);
pF = NULL;
int output = *it;
cout << "The occurrence of " << find << " is:" << ctr << endl;
cout << "The first occurrence is " << output << endl;
cin.clear();
int ival = 0;
/*
// read cin and test only for EOF; loop is executed even if there are other IO failures
while (cin >> ival, !cin.eof()) {
if (cin.bad()) // input stream is corrupted; bail out
throw runtime_error("IO stream corrupted");
if (cin.fail()) { // bad input
cerr << "bad data, try again" << endl; // warn the user
//cin.clear(istream::failbit); // reset the stream
cout << cin.rdstate() << endl;
//cin.clear();
//cout << cin.rdstate() << endl;
// get next input
}
// ok to process ival
}
*/
}
int main() {
Sales_item item;
cout << item.avg_price() << endl;
test();
return 0;
}