（1） Input and output

（ One ） Input and output

1、 Read

#include <iostream>
#include <cstring>
using namespace std;

int main()
{
    

    int a;
    int i[10];
    memset(i,0,sizeof(i));

    while(scanf("%d",&a) != EOF){
    
            i[0]++;
    }
    cout<<"（1） "<<i[0]<<endl;

    while(cin>>a){
    
            i[1]++;
    }
    cout<<"(2) "<<i[1]<<endl;

    while(scanf("%d",&a)!=-1){
    
        i[3]++;
    }
    cout<<"(3) "<<i[3]<<endl;

    return 0;
}

result ：

2、 Output

#include <iostream>
#include <iomanip>
using namespace std;


int main()
{
    
    // left right fixed scientific setprecision setfill  It has aftereffect 
    // setw(10)  No aftereffect 
    // fixed and setprecision The role of . As long as you set up , Will always be （ Unless you put fixed eliminate ,setprecision（） modify ）
    //%md m Bit right aligned output , High fill space 
    //%0md m Bit right aligned output , High compensation 0

    double n;
    cin>>n;
    cout<<n<<endl; //  Default to 6 precision , So the output is  12.3457

    //  Think of it this way , Omitted by default setprecision(6) This code 
    cout << setprecision(4) << n << endl; //  Change to 4 precision , So the output is 12.35
    cout << "-------" << endl;


    cout << fixed << setprecision(4) << n << endl;
    //  added fixed It means fixed point display , So here precision refers to decimal places , Output is 12.3457

    cout <<  n << endl;
    // fixed and setprecision The role of , Still show 12.3457

    cout.unsetf( ios::fixed );
    //  Removed fixed, So the accuracy is restored to the significant digits of the whole value , Is shown as 12.35 setprecision(4) The role of still exists 
    cout << n << endl;
    //  Return to the original , Output is 12.3457
    cout << "-------" << endl;


    cout << setprecision(6) << n << endl;
    cout << scientific << n << endl; // scientific And  fixed  similar   One is scientific counting , One is in decimal form 
    cout.unsetf( ios::scientific);
    cout << n << endl;
    cout << "-------" << endl;


    // setfill It must be written at the beginning 
    cout << setfill('*')<< right << setw(10) << n <<  endl;
    cout << setfill('#')<< setw(10) << n <<  endl;

    // setw(10)  No aftereffect   So it needs to be in every n with 
    cout << setfill('*')<< left <<  n <<  endl;
    cout << setfill('#')<< setw(10) << n <<  endl;
    cout<<"-------"<<endl;


    int m;
    cin>>m;
    printf("%6d\n",m);  //%md m Bit right aligned output , High fill space 
    printf("%06d\n",m);//%0md m Bit right aligned output , High compensation 0



    return 0;

}

Output results