未在函数 C++ 中执行的循环

Question

Here's my code. Whenever I run the program, I expect that the statement in the in the function to execute. But whenever I input something, it gives me

#include<iostream>
#include<math.h>
using namespace std;
long int Binary(int x){
    int temp=0,res=0;
    for(int i=x;i<0;i--){
        temp++;
        res=res+ pow(10,temp)*(i%2);
        i=i/2;
        cout<<i<<"  "<<res<<endl;
    }
    return res;
} 
int main(){
    int x; cin>>x;
    cout<<endl<<Binary(x);
    return 0;
}

Answer 1

I think the condition in your for loop is the opposite way round than your expect it. You seem to want it to continue looping until i<0 . But it will actually loop while i<0 . The condition is already not true when you enter the loop, so it will finish immediately without doing any iterations.

Answer 2

You just have to change the loop i check.

#include<iostream>
#include<math.h>
using namespace std;
long int Binary(int x){
    int temp=0,res=0;
    for(int i=x;i>0;i--){
        temp++;
        res=res+ pow(10,temp)*(i%2);
        i=i/2;
        cout<<i<<"  "<<res<<endl;
    }
    return res;
} 
int main(){
    int x; cin>>x;
    cout<<endl<<Binary(x);
    return 0;
}

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