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; }