Error with the algorithm for finding prime numbers
closed account (zbfzwbRD)
I want to find all the prime numbers in the given numbers, but I can't.
For example
8
3 4 5 7 9 -9 -7 0
the output should be
4
and I have 5
#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
using namespace std;
bool IsPrime(int x){
x = abs(x);
if(x == 2){
return true;
}
bool test = true;
for(int i=2; i*i<=x; i++){
if(x%i==0){
test = false;
break;
}else{
test = true;
}
}
return test;
}
int main(){
int n;
cin >> n;
vector<int> v;
for(int i=0; i<=n; i++){
int x;
cin >> x;
v.push_back(x);
}
int cnt = count_if(v.begin(), v.end(), IsPrime);
cout << cnt;
}
For example
8
3 4 5 7 9 -9 -7 0
the output should be
4
and I have 5
#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
using namespace std;
bool IsPrime(int x){
x = abs(x);
if(x == 2){
return true;
}
bool test = true;
for(int i=2; i*i<=x; i++){
if(x%i==0){
test = false;
break;
}else{
test = true;
}
}
return test;
}
int main(){
int n;
cin >> n;
vector<int> v;
for(int i=0; i<=n; i++){
int x;
cin >> x;
v.push_back(x);
}
int cnt = count_if(v.begin(), v.end(), IsPrime);
cout << cnt;
}
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