【额外练习】选择结构/7-1 选择-孔融让梨.c

@@ -1,15 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int a, b;
-
-    scanf("%d%d", &a, &b);
-
-    if (a < b) {
-        printf("%d\n", a);
-    } else {
-        printf("%d\n", b);
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-10 选择-三角形分类.c

@@ -1,17 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int a, b, c;
-
-    scanf("%d%d%d", &a, &b, &c);
-
-    if (a == b && b == c) {
-        printf("bian\n");
-    } else if (a == b || b == c || a == c) {
-        printf("yao\n");
-    } else {
-        printf("triangle\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-11 选择-五分制转百分制.c

@@ -1,21 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    char grade;
-
-    scanf("%c", &grade);
-
-    if (grade == 'A') {
-        printf("85~100\n");
-    } else if (grade == 'B') {
-        printf("70~84\n");
-    } else if (grade == 'C') {
-        printf("60~69\n");
-    } else if (grade == 'D') {
-        printf("<60\n");
-    } else {
-        printf("Error\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-12 选择-大小写转换.c

@@ -1,15 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    char c;
-
-    scanf("%c", &c);
-
-    if (c >= 'a' && c <= 'z') {
-        printf("%c\n", c - 32);
-    } else if (c >= 'A' && c <= 'Z') {
-        printf("%c\n", c + 32);
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-13 选择-体积最大.c

@@ -1,17 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int a, b, c;
-
-    scanf("%d%d%d", &a, &b, &c);
-
-    if (a > b && a > c) {
-        printf("%d\n", a);
-    } else if (b > a && b > c) {
-        printf("%d\n", b);
-    } else {
-        printf("%d\n", c);
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-14 选择-N以内所有正整数和.c

@@ -1,16 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int n;
-    int sum = 0;
-
-    scanf("%d", &n);
-
-    for (int i = 1; i <= n; i++) {
-        sum += i;
-    }
-
-    printf("%d\n", sum);
-
-    return 0;
-}

【额外练习】选择结构/7-15 选择-简易计算机.c

@@ -1,51 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int x, a, b, c;
-
-    scanf("%d%d%d%d", &x, &a, &b, &c);
-
-    switch (x) {
-        case 0:
-            printf("%d", a + b);
-            break;
-
-        case 1:
-            printf("%d", a - b);
-            break;
-
-        case 2:
-            printf("%d", a * b);
-            break;
-
-        case 3:
-            printf("%d", a / b);
-            break;
-
-        case 4:
-            printf("%d", a % b);
-            break;
-
-        case 5:
-            printf("%d", a ? b : c);
-            break;
-
-        case 6:
-            printf("%d", a > b);
-            break;
-
-        case 7:
-            printf("%d", a < b);
-            break;
-
-        case 8:
-            printf("%d", a != b);
-            break;
-
-        case 9:
-            printf("%d", a == b);
-            break;
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-16 选择-简单的运算.c

@@ -1,12 +0,0 @@
-#include <math.h>
-#include <stdio.h>
-
-int main() {
-    double n;
-
-    scanf("%lf", &n);
-
-    printf("%d %d %.5lf\n", (int)ceil(n), (int)floor(n), n);
-
-    return 0;
-}

【额外练习】选择结构/7-17 选择-水仙花数.c

@@ -1,19 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int n;
-
-    scanf("%d", &n);
-
-    int a = n / 100;
-    int b = n / 10 % 10;
-    int c = n % 10;
-
-    if (n == a * a * a + b * b * b + c * c * c) {
-        printf("yes\n");
-    } else {
-        printf("no\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-18 选择-三角形面积.c

@@ -1,17 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    double a, b, c;
-
-    scanf("%lf%lf%lf", &a, &b, &c);
-
-    if (a + b > c && a + c > b && b + c > a) {
-        double p = (a + b + c) / 2;
-        double s = sqrt(p * (p - a) * (p - b) * (p - c));
-        printf("%.2lf %.2lf\n", s, a + b + c);
-    } else {
-        printf("no triangle\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-19 选择-完全平方数.c

@@ -1,18 +0,0 @@
-#include <math.h>
-#include <stdio.h>
-
-int main() {
-    int n;
-
-    scanf("%d", &n);
-
-    int m = sqrt(n);
-
-    if (m * m == n) {
-        printf("Yes\n");
-    } else {
-        printf("No\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-2 选择-奇偶判断.c

@@ -1,15 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int a;
-
-    scanf("%d", &a);
-
-    if (a % 2 == 1) {
-        printf("YES\n");
-    } else {
-        printf("NO\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-20 选择-矩形与点的位置.c

@@ -1,15 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int xL, yL, xR, yR, x, y;
-
-    scanf("%d%d%d%d%d%d", &xL, &yL, &xR, &yR, &x, &y);
-
-    if (x >= xL && x <= xR && y <= yL && y >= yR) {
-        printf("Yes\n");
-    } else {
-        printf("No\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-21 选择-数的判别.c

@@ -1,17 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int n;
-
-    scanf("%d", &n);
-
-    if (n % 2 == 0) {
-        printf("%d is an even number\n", n);
-    } else if (n % 3 == 0) {
-        printf("%d is an odd number,it can be divided by 3\n", n);
-    } else {
-        printf("%d is an odd number,it can't be divided by 3\n", n);
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-22 选择-销售菜单.c

@@ -1,31 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int n;
-
-    scanf("%d", &n);
-
-    switch (n) {
-        case 1:
-            printf("8\n");
-            break;
-
-        case 2:
-            printf("4.5\n");
-            break;
-
-        case 3:
-            printf("12.8\n");
-            break;
-
-        case 4:
-            printf("3\n");
-            break;
-
-        default:
-            printf("Exit\n");
-            break;
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-23 选择-电话费.c

@@ -1,20 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int t;
-
-    scanf("%d", &t);
-
-    double s1 = 25 + 0.1 * t;
-    double s2 = 20;
-
-    if (t >= 100) s2 = 0.3 * t;
-
-    if (s1 > s2) {
-        printf("2\n");
-    } else {
-        printf("1\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-24 选择-税收计算1.c

@@ -1,17 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int x;
-
-    scanf("%d", &x);
-
-    if (x <= 800) {
-        printf("0.0\n");
-    } else if (x <= 4000) {
-        printf("%.1lf\n", (x - 800) * 0.15);
-    } else {
-        printf("%.1lf\n", x * 0.1);
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-25 选择-自然数.c

@@ -1,15 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    double a;
-
-    scanf("%lf", &a);
-
-    if (a >= 0 && (int)a == a) {
-        printf("Yes\n");
-    } else {
-        printf("No\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-26 选择-宝藏.c

@@ -1,31 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int x;
-
-    scanf("%d", &x);
-
-    int canFill = 0;
-
-    for (int a = 0; a <= x / 4; a++) {
-        for (int b = 0; b <= x / 5; b++) {
-            for (int c = 0; c <= x / 7; c++) {
-                // 计算当前组合的体积
-                if (4 * a + 5 * b + 7 * c == x) {
-                    canFill = 1;
-                    break;
-                }
-            }
-            if (canFill) break;
-        }
-        if (canFill) break;
-    }
-
-    if (canFill) {
-        printf("ni bu yao guo lai a!\n");
-    } else {
-        printf("What a lucky day!\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-27 选择-回文数.c

@@ -1,24 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int n;
-    int a, b, c, d, e, f, g;
-
-    scanf("%d", &n);
-
-    a = n / 1000000;
-    b = n / 100000 % 10;
-    c = n / 10000 % 10;
-    d = n / 1000 % 10;
-    e = n / 100 % 10;
-    f = n / 10 % 10;
-    g = n % 10;
-
-    if (a == g && b == f && c == e) {
-        printf("Yes\n");
-    } else {
-        printf("No\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-28 选择-时钟.c

@@ -1,16 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int h, m;
-
-    scanf("%d:%d", &h, &m);
-
-    double angle = 30 * h - 5.5 * m;
-
-    if (angle < 0) angle = -angle;
-    if (angle > 180) angle = 360 - angle;
-
-    printf("%.3lf\n", angle);
-
-    return 0;
-}

【额外练习】选择结构/7-29 选择-求解一元二次方程.c

@@ -1,31 +0,0 @@
-#include <math.h>
-#include <stdio.h>
-
-int main() {
-    double a, b, c;
-
-    scanf("%lf%lf%lf", &a, &b, &c);
-
-    double delta = b * b - 4 * a * c;
-
-    if (delta > 0) {
-        double x1 = (-b - sqrt(delta)) / (a * 2);
-        double x2 = (-b + sqrt(delta)) / (a * 2);
-
-        if (x1 > x2) {
-            double temp = x1;
-            x1 = x2;
-            x2 = temp;
-        }
-
-        printf("%.2lf %.2lf\n", x1, x2);
-    } else if (delta == 0) {
-        double x1 = -b / (a * 2);
-
-        printf("%.2lf\n", x1);
-    } else {
-        printf("No solution\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-3 选择-ASCII值.c

@@ -1,15 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    char c;
-
-    scanf("%c", &c);
-
-    if ('0' <= c && c <= '9') {
-        printf("%d\n", c);
-    } else {
-        printf("input error\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-30 选择-硬币游戏.c

@@ -1,20 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int a, b;
-
-    scanf("%d%d", &a, &b);
-
-    // [Theorem]
-    // In a normal nim game, the player making the first move has a winning strategy
-    // if and only if the nim-sum of the sizes of the heaps is not zero. Otherwise,
-    // the second player has a winning strategy.
-    // Source: https://en.wikipedia.org/wiki/Nim
-    if ((a ^ b) == 0) {
-        printf("abcdxyzk\n");
-    } else {
-        printf("AekdyCoin\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-31 选择-猜数字游戏.c

@@ -1,29 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int total, andy, ban;
-
-    scanf("%d%d%d", &total, &andy, &ban);
-
-    int andyDiff = total - andy;
-    int banDiff = total - ban;
-
-    if (andyDiff < 0) andyDiff = -andyDiff;
-    if (banDiff < 0) banDiff = -banDiff;
-
-    if (andyDiff == banDiff) {
-        if (andy < ban) {
-            printf("Andy\n");
-        } else if (andy == ban) {
-            printf("Peace\n");
-        } else {
-            printf("Ban\n");
-        }
-    } else if (andyDiff < banDiff) {
-        printf("Andy\n");
-    } else {
-        printf("Ban\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-32 选择-扑克.c

@@ -1,21 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int n;
-
-    scanf("%d", &n);
-
-    if (n >= 1 && n <= 10) {
-        printf("%d\n", n);
-    } else if (n == 11) {
-        printf("J\n");
-    } else if (n == 12) {
-        printf("Q\n");
-    } else if (n == 13) {
-        printf("K\n");
-    } else {
-        printf("NO\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-4 选择-闰年.c

@@ -1,15 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int year;
-
-    scanf("%d", &year);
-
-    if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) {
-        printf("YES\n");
-    } else {
-        printf("NO\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-5 选择-排序.c

@@ -1,15 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    double a, b;
-
-    scanf("%lf%lf", &a, &b);
-
-    if (a > b) {
-        printf("%.3lf %.3lf\n", a, b);
-    } else {
-        printf("%.3lf %.3lf\n", b, a);
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-6 选择-分段函数3.c

@@ -1,18 +0,0 @@
-#include <math.h>
-#include <stdio.h>
-
-int main() {
-    double x;
-
-    scanf("%lf", &x);
-
-    if (x < 1) {
-        printf("%.3lf\n", x);
-    } else if (1 <= x && x < 10) {
-        printf("%.3lf\n", sqrt(x * 2 - 1));
-    } else {  // x >= 10
-        printf("%.3lf\n", log(x * 3 - 11));
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-7 选择-圆塔.c

@@ -1,18 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    double x, y;
-
-    scanf("%lf%lf", &x, &y);
-
-    if ((x - 2) * (x - 2) + (y - 2) * (y - 2) <= 1
-        || (x + 2) * (x + 2) + (y - 2) * (y - 2) <= 1
-        || (x + 2) * (x + 2) + (y + 2) * (y + 2) <= 1
-        || (x - 2) * (x - 2) + (y + 2) * (y + 2) <= 1) {
-        printf("10\n");
-    } else {
-        printf("0\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-8 选择-买奶茶.c

@@ -1,19 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int x;
-
-    scanf("%d", &x);
-
-    if (x == 5) {
-        printf("6\n");
-    } else if (x == 6) {
-        printf("10\n");
-    } else if (x == 7) {
-        printf("8\n");
-    } else {
-        printf("4\n");
-    }
-
-    return 0;
-}

【额外练习】选择结构/7-9 选择-三角形判别.c

@@ -1,15 +0,0 @@
-#include <stdio.h>
-
-int main() {
-    int a, b, c;
-
-    scanf("%d%d%d", &a, &b, &c);
-
-    if (a + b > c && a + c > b && b + c > a) {
-        printf("Yes\n");
-    } else {
-        printf("No\n");
-    }
-
-    return 0;
-}