[practice]cpp primer 1 script

1

practice $1.3

#include<iostream>int main(){   std::cout << "Hello world!" << std::endl;     return 0;}

shell

g++ -o prog1 prog1.cc
./prog1

$1.4
$1.5

#include<iostream>int main(){   std::cout << "Enter two numbers:";   std::cout <<  std::endl;   int v1 = 0, v2 = 0;   std::cin >> v1;   std::cin >> v2;   std::cout << v1 ;   std::cout << " times ";   std::cout << v2 ;   std::cout << " equals ";   std::cout <<v1*v2;   std::cout <<std::endl;   return 0;}

$1.6
wrong

$1.9

#include<iostream>int main(){    int sum = 0, vol = 50;    while(vol <= 100)    {        sum += vol;        vol++;    }    std::cout << "The sum of 50 to 100 inclusive is " <<sum<<std::endl;    return 0;}

$1.10

#include<iostream>int main(){    int vol = 10;    while(vol--)    {        std::cout << vol << std::endl;    }    return 0;}

print [9 :0]’

$1.11(19)
python range() fake

#include<iostream>int main(){    int v1 = 0, v2 = 0;    std::cout << "Input two value:" << std::endl;    std::cin >> v1 >> v2;    if(v1 > v2)    {        v1 = v1 ^ v2;        v2 = v1 ^ v2;        v1 = v1 ^ v2;    }    while(v1 < v2)    {        std::cout << v1 << std::endl;        v1++;    }    return 0;}

$1.13

#include<iostream>int main(){    int sum = 0;    for(int i = 50; i <= 100; i++)    {        sum += i;    }    std::cout << sum << std::endl;    return 0;}

#include<iostream>int main(){    std::cout << "$1.9" << std::endl;    int sum = 0;    for(int i = 50; i <= 100; i++)    {        sum += i;    }    std::cout << sum << "\n$1.10 "<<std::endl;    for(int i = 10; i >= 0; i--)    {        std::cout << i << std::endl;    }    std::cout << "$1.11" <<std::endl;    int v1 = 0, v2 = 0;    std::cout << "Input two number" << std::endl;    std::cin >> v1 >> v2;    for(int i = v1; i <= v2; i++)    {        std::cout << i << std::endl;    }    return 0;

$1.16

#include<iostream>int main(){    int sum = 0, i = 0;    std::cout << "Input numbers:" << std::endl;    while( std::cin >> i)    {        sum += i;    }    std::cout << sum <<std::endl;    return 0;}

echo “1 2 3 | ./out”

$1.17-8

#include<iostream>using namespace std;int main(){    int currval = 0, val = 0;    if(cin >> currval) {        int cnt = 1;        while(cin >> val) {            if(val == currval)                cnt++;            else {                cout << currval << " occours "  << cnt << " times " << endl;                 cnt = 1;                currval = val;            }        }        cout << currval << " occours "  << cnt << " times " << endl;     }    return 0;}

pi@pi:~/script/cpp$ echo “1 1 1 1 2 2 2 3 3 3 4 4 5 6” | ./out
1 occours 4 times
2 occours 3 times
3 occours 3 times
4 occours 2 times
5 occours 1 times
6 occours 1 times

#include<iostream>using namespace std;int main(){    unsigned u = 10, u2 = 42;    cout << u - u2 << endl; //4294967264=2^32-32    cout << u2 - u << endl; //32    int i = 10, i2 = 42;    cout << i - i2 << endl; //-32    cout << i2 - i << endl; //32    cout << i - u << endl;  //0    cout << u - i << endl;  //0    return 0;}