流提取运算符和流插入运算符的有关问题
流提取运算符和流插入运算符的问题
这个程序运行的时候,我输入2.2 3.4为什么输出的是0.2 0.4 而不是2.2 3.4
程序是这个:
#include<iostream>
using namespace std;
class Complex
{
public:
Complex(double r=0,double i=0);
friend ostream &operator<<(ostream &ost,Complex &c);
friend istream &operator>>(istream &ist,Complex &c);
private:
double real,image;
};
Complex::Complex(double r,double i)
{
real=r;
image=i;
}
ostream &operator<<(ostream &ost,Complex &c)
{
ost<<"("<<c.real<<","<<c.image<<")"<<endl;
return ost;
}
istream &operator>>(istream &ist,Complex &c)
{
cout<<"请输入复数的实部和虚部,如(2.5,3.5):"<<endl;
char ch;
ist>>ch>>c.real>>ch>>c.image;
return ist;
}
void main()
{
Complex a;
cin>>a;
cout<<a;
}
------解决方案--------------------
仅供参考
------解决方案--------------------
ch是char,能接受数字?
这个程序运行的时候,我输入2.2 3.4为什么输出的是0.2 0.4 而不是2.2 3.4
程序是这个:
#include<iostream>
using namespace std;
class Complex
{
public:
Complex(double r=0,double i=0);
friend ostream &operator<<(ostream &ost,Complex &c);
friend istream &operator>>(istream &ist,Complex &c);
private:
double real,image;
};
Complex::Complex(double r,double i)
{
real=r;
image=i;
}
ostream &operator<<(ostream &ost,Complex &c)
{
ost<<"("<<c.real<<","<<c.image<<")"<<endl;
return ost;
}
istream &operator>>(istream &ist,Complex &c)
{
cout<<"请输入复数的实部和虚部,如(2.5,3.5):"<<endl;
char ch;
ist>>ch>>c.real>>ch>>c.image;
return ist;
}
void main()
{
Complex a;
cin>>a;
cout<<a;
}
------解决方案--------------------
仅供参考
#include <stdio.h>
char s[]="123 ab 4";
char *p;
int v,n,k;
void main() {
p=s;
while (1) {
k=sscanf(p,"%d%n",&v,&n);
printf("k,v,n=%d,%d,%d\n",k,v,n);
if (1==k) {
p+=n;
} else if (0==k) {
printf("skip char[%c]\n",p[0]);
p++;
} else {//EOF==k
break;
}
}
printf("End.\n");
}
//k,v,n=1,123,3
//k,v,n=0,123,3
//skip char[ ]
//k,v,n=0,123,3
//skip char[a]
//k,v,n=0,123,3
//skip char[b]
//k,v,n=1,4,2
//k,v,n=-1,4,2
//End.
------解决方案--------------------
ch是char,能接受数字?