六、循环结构

#include <stdio.h>

int main() {
    int T;
    
    
    scanf("%d", &T);
    
    
    for (int i = 0; i < T; i++) {
        int a, b;
        
        
        scanf("%d %d", &a, &b);
        
     
        int sum = a + b;
        printf("%d\n", sum);
    }
    
    return 0;
}

#include <stdio.h>

int main() {
    int a, b;
    
   
    while (1) {
        
        scanf("%d %d", &a, &b);
      
        if (a == 0 && b == 0) {
            break; 
        }
        
       
        int sum = a + b;
        printf("%d\n", sum);
    }
    
    return 0;
}

#include <stdio.h>
#include <math.h> 
int isPrime(int n) {
   
    if (n <= 1) {
        return 0;
    }
    
    
    if (n == 2) {
        return 1;
    }
    
    
    if (n % 2 == 0) {
        return 0;
    }
    
    
    for (int i = 3; i <= sqrt(n); i += 2) {
        if (n % i == 0) {
            return 0;
        }
    }
    
   
    return 1;
}

int main() {
    int T;
    
    
    scanf("%d", &T);
    
    
    for (int i = 0; i < T; i++) {
        int n;
        
        
        scanf("%d", &n);
        
     
        if (isPrime(n)) {
            printf("Yes\n");
        } else {
            printf("No\n");
        }
    }
    
    return 0;
}

#include <stdio.h>

int main() {
    int n;
    
  
    scanf("%d", &n);
    
    int sum = 0; 
    
 
    for (int i = 1; i <= n; i++) {
       
        if (i % 2 == 1) { 
            sum += i;     
        } else {          
            sum -= i;    
        }
    }
    
    
    printf("%d\n", sum);
    
    return 0;
}

#include <stdio.h>

int main() {
    int n;
    
    
    scanf("%d", &n);
    
  
    double sum = 0.0;
    
   
    for (int i = 1; i <= n; i++) {
      
        sum += 1.0 / i;
    }
    
  
    printf("%.10f\n", sum);
    
    return 0;
}

#include <stdio.h>
#include <limits.h> 

int main() {
    int n;
    
   
    scanf("%d", &n);
    
    int arr[100000]; 
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }
    
    
    int max_val = arr[0];
    int min_val = arr[0];
    
    for (int i = 1; i < n; i++) {
        if (arr[i] > max_val) {
            max_val = arr[i];
        }
        if (arr[i] < min_val) {
            min_val = arr[i];
        }
    }
    
    int max_diff = max_val - min_val;
    printf("%d\n", max_diff);
    
    return 0;
}

#include <stdio.h>

int main() {
    int n;
    
    
    scanf("%d", &n);
    
    int total_sum = 0; 
    
   
    for (int i = 1; i <= n; i++) {
        int current_sum = 0; 
        for (int j = 1; j <= i; j++) {
            current_sum += j;
        }
        
        
        total_sum += current_sum;
    }
    
    
    printf("%d\n", total_sum);
    
    return 0;
}

#include <stdio.h>

int main() {
    int n;
    scanf("%d", &n);
    
    
    if (n == 1 || n == 2) {
        printf("1\n");
        return 0;
    }
    
   
    int prev_prev = 1; 
    int prev = 1;      
    int current;       
    
    for (int i = 3; i <= n; i++) {
        current = prev + prev_prev;
        prev_prev = prev; 
        prev = current;   
    }
    
    printf("%d\n", current);
    return 0;
}

#include <stdio.h>

int main() {
    long long n; 
    scanf("%lld", &n);
    
    
    if (n < 0) {
        n = -n;
    }
    
    int sum = 0;
    
    do {
        sum += n % 10; 
        n = n / 10;   
    } while (n != 0);
    
    printf("%d\n", sum);
    return 0;
}

#include <stdio.h>


int hasDigit4(int num) {
    while (num > 0) {
        if (num % 10 == 4) { 
            return 1;
        }
        num = num / 10; 
    }
    return 0;
}

int main() {
    int n;
    scanf("%d", &n);
    
    for (int i = 1; i <= n; i++) {
        
        if (i % 4 != 0 && !hasDigit4(i)) {
            printf("%d\n", i);
        }
    }
    
    return 0;
}