c++ primer 第五版1.4节练习

练习1.9

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

 } 

练习1.10

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

 } 

练习1.11

#include <iostream>
int main()
{
std::cout<<"Enter two numbers"<<std::endl;
int a=0,b=0;
std::cin>>a>>b;
while(a<=b){
std::cout<<a<<std::cout;
++a;
}
return 0; 
 }