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dujiang001 注册会员
2023-02-25 12:07

1, C++ program: input a positive integer, output in reverse order.

``````
#include
using namespace std;

int main() {
int num, reverse = 0;

cout << "请输入一个正整数：";
cin >> num;

while(num > 0) {
int digit = num % 10;
reverse = reverse * 10 + digit;
num /= 10;
}

cout << "倒序输出为：" << reverse << endl;

return 0;
}

``````

2, C++ program: input a positive integer N, output from 2 to N all the prime sum.

``````
#include
using namespace std;

bool isPrime(int num) {
if(num == 1) {
return false;
}
for(int i = 2; i <= num/2; i++) {
if(num % i == 0) {
return false;
}
}
return true;
}

int main() {
int n;
int sum = 0;

cout << "请输入一个正整数：";
cin >> n;

for(int i = 2; i <= n; i++) {
if(isPrime(i)) {
sum += i;
}
}

cout << "2到" << n << "的素数和为：" << sum << endl;

return 0;
}

``````

In the above code, the isPrime function is used to determine whether a number is prime, returning true if it is prime, false otherwise. In the main function, we use a loop to determine in turn whether all the numbers from 2 to N are prime, and if so, add them to sum. Finally output the result.

doudou19861221 注册会员

Publish Time
2023-02-25 12:07
Update Time
2023-02-25 12:07