四、顺序结构

#include <stdio.h>

int main() {
    int n;
    scanf("%d", &n);  
    int a = n / 1000;   
    int b = (n / 100) % 10; 
    int c = (n / 10) % 10;   
    int d = n % 10;      
    
   
    printf("%d%d%d%d\n", d,c,b,a);
    
    return 0;
}

#include <stdio.h>
int main()
 {
    double K;
    scanf("%lf", &K);
    double C = K - 273.15;
    double F = C * 1.8;
    F = F + 32;
    printf("%.10lf\n", F);
    return 0;
}

#include <stdio.h>
#include <math.h> 

int main() {
    int x1, y1, x2, y2;
   
    scanf("%d %d", &x1, &y1);
    scanf("%d %d", &x2, &y2);
    
    
    int dx = abs(x1 - x2);
    int dy = abs(y1 - y2);
    
   
    double dM = dx + dy;
  
    double dE = sqrt(dx * dx + dy * dy);
   
    double delta = fabs(dM - dE);
    
    printf("%.6f\n", delta);
    
    return 0;
}

#include <stdio.h>

int main() {
    int n;
    scanf("%d", &n); 
    
    int a = n % 10;
    int b = (n / 10) % 10;
    int c = (n / 100) % 10;
    int d = n / 1000;
   
    int sum = a + b + c + d;
    printf("%d\n", sum);
    
    return 0;
}

#include <stdio.h>

int main() {
    long long seconds; 
    scanf("%lld", &seconds);
    
    int hours = seconds / 3600;
    int remaining = seconds % 3600;
    int minutes = remaining / 60;
    int secs = remaining % 60;
    
    printf("%d %d %d\n", hours, minutes, secs);
    return 0;
}

#include <stdio.h>

int main() {
    int n;
    scanf("%d", &n);
    long long count = (long long)n * 1024 * 1024 / 4;
    printf("%lld\n", count);
    return 0;
}

#include <stdio.h>

int main() {
    int a, b, c;
    scanf("%d %d %d", &a, &b, &c); 
    
    int surface = 2 * (a*b + a*c + b*c);
    int volume = a * b * c;
    
    printf("%d\n%d\n", surface, volume);
    return 0;
}

 #include <stdio.h>

int main() {
    int A, B, C;
    scanf("%d %d %d", &A, &B, &C);
  
    int S = A * 0.2 + B * 0.3 + C * 0.5;
    printf("%d\n", S);
    return 0;
}

#include <stdio.h>

int main() {
    long long n;
    scanf("%lld", &n);
    long long sum = n * (n + 1) / 2;
    printf("%lld\n", sum);
    return 0;
}