1 public class math { 2 public static void subject(Object obj) { 3 System.out.println(obj); 4 } 5 public static void main(String[] args) { 6 subject("四则运算题："); 7 int count = 0; 8 for (int i = 0; i < 300; i++) { 9 int d1 = (int) ((Math.random()) * 100); 10 int d2 = (int) ((Math.random()) * 100); 11 int k = (int) ((Math.random()) * 100); 12 int k2 = (int) ((Math.random()) * 100); 13 int k3 = (int) ((Math.random()) * 100); 14 int k4 = (int) ((Math.random()) * 100); 15 int x = 1; 16 if (0 <= k && k < 12) 17 x = 1; 18 else if (12 <= k && k < 24) 19 x = 2; 20 else if (24 <= k && k < 36) 21 x = 3; 22 else if (36 <= k && k < 48) 23 x = 4; 24 else if (48 <= k && k < 60) 25 x = 5; 26 else if (60 <= k && k < 72) 27 x = 6; 28 else if (72 <= k && k < 84) 29 x = 7; 30 else 31 x = 8; 32 switch (x) { 33 case 1: 34 subject(d1 + "+" + d2 + "="); 35 break; 36 case 2: 37 jiafa(d1, d2); 38 break; 39 case 3: 40 subject(d1 + "*" + d2 + "="); 41 break; 42 case 4: 43 chufa(d1, d2); 44 break; 45 case 5: 46 subject(zhenfenshu(k, k2) + "+" + zhenfenshu(k3, k4) + "="); 47 break; 48 case 6: 49 subject(zhenfenshu(k, k2) + "-" + zhenfenshu(k3, k4) + "="); 50 break; 51 case 7: 52 subject(zhenfenshu(k, k2) + "*" + zhenfenshu(k3, k4) + "="); 53 break; 54 case 8: 55 subject(zhenfenshu(k, k2) + "/" + zhenfenshu(k3, k4) + "="); 56 break; 57 default: 58 subject("stop,stop,stop"); 59 break; 60 } 61 count++; 62 } 63 subject("以上共有" + count + "道四则运算练习题！"); 64 } 65 public static void jiafa(int a, int b) { 66 if (a > b) 67 subject(a + "-" + b + "="); 68 else { 69 subject(b + "-" + a + "="); 70 } 71 } 72 public static void chufa(int a, int b) { 73 if (b > 0) 74 subject(a + "/" + b + "="); 75 else { 76 b = b + 10; 77 subject(a + "/" + b + "="); 78 } 79 } 80 public static String zhenfenshu(int a, int b) { 81 if (a <= b) 82 return a + "/" + b; 83 else 84 return b + "/" + a; 85 } 86 87 }
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