1 //---------------------1
2 #include<stdio.h>
3 void main()
4 {
5 int a,b,c;
6 printf("输入三个正整数,a,b,c");
7 scanf("%d%d%d",&a,&b,&c);
8 if(a>b&&a>c)//很好的算法，求出三个数的最大值
9 if(b>c)
10 printf("%d%d%d\n",a,b,c);
11 else
12 printf("%d%d%d",a,c,b);
13 else if(b>a&&b>c)
14 if(a>c)
15 printf("%d%d%d\n",b,a,c);
16 else
17 printf("%d%d%d\n",b,c,a);
18 else
19 if(a>b)
20 printf("%d%d%d\n",c,a,b);
21 else
22 printf("%d%d%d\n",c,b,a);
23 }
24 //---------------2
25 #include<stdio.h>
26 void main()
27 {
28 int a,b,c,t;
29 printf("输入三个正整数a,b,c");
30 scanf("%d%d%d",&a,&b,&c);
31 if(a<b)
32 {t=a;a=b;b=t;}
33 if(a<c)
34 {t=b;a=c;c=t;}
35 if(b<c)
36 {t=b;b=c;c=t;}
37 printf("%d%d%d\n",a,b,c);
38 }
39 //----------------------------3
40 #include<stdio.h>
41 void main()
42 {
43 int g;
44 printf("输入成绩:g");
45 scanf("%d",&g);
46 if(g>=85&&g<=100)
47 printf("优秀");
48 else
49 if(g>=75&&g<=84)
50 printf("良好");
51 else
52 if(g>=64&&g<=74)
53 printf("及格");
54 else
55 printf("不及格");
56 }
57 //----------------------4
58 #include<stdio.h>
59 void main()
60 {
61 int d;
62 printf("输入一个正整数:\n");
63 scanf("%d",&d);
64 switch (d)
65 {
66 case 1:printf("monday\n");break;
67 case 2:printf("tuesday\n");break;
68 case 3:printf("wednesday\n");break;
69 case 4:printf("thursday\n");break;
70 case 5:printf("friday\n");break;
71 case 6:printf("saturday\n");break;
72 case 7:printf("sunday\n");break;
73 default:printf("you input error?\n");break;
74 }
75 }
76 //---------------------------------5
77 #include<stdio.h>
78 void main()
79 {
80 int year,month;
81 printf("输入年和月:");
82 scanf("%d%d",&year,&month);
83 switch (month)
84 {
85 case 1:
86 case 3:
87 case 5:
88 case 7:
89 case 8:
90 case 10:
91 case 12:
92 printf("%d%d has 31 days\n.",year,month);break;
93 case 4:
94 case 6:
95 case 9:
96 case 11:
97 printf("%d%d has 30 days\n",year,month);break;
98 case 2:
99 if(year%4==0&&year%100!=0||year%400==0)
100 {printf("%d%d has 29 days\n.",year,month);break;}
101 else
102 {
103
104 printf("%d%d has 28 days\n.",year,month);break;
105 }
106 default:
107 printf("you input error!\n");
108 }
109 }
110 //-----------------------------6
111 #include<stdio.h>
112 void main()
113 {
114 int c;
115 printf("Enter 1 or 0");
116 scanf("%d",&c);
117 while(c==1)
118 {
119 printf("*******\n");
120 printf("Enter 1 or 0");
121 scanf("%d",&c);//突然想起和那个递归的形式差不多
122 }
123 }
124 //-----------------------------7
125 #include<stdio.h>
126 void main()
127 {
128 int c;
129 do
130 {
131 printf("*******\n");
132 printf("Enter 1 or 0");
133 scanf("%d",&c);
134 }while (c==1);
135 }
136 //-----------------------------8
137 #include<stdio.h>
138 void main()
139 {
140 int i,n;
141 printf("Enter role n:");
142 scanf("%d",&n);
143 for(i=0;i<=n;i++)//n+1行
144 {
145 printf("*******");
146 printf("\n");
147 }
148 }
149 //-----------------------------9
150 #include<stdio.h>
151 void main()
152 {
153 int i,s=0;
154 for(i=1;i<=10;i++)
155 {
156 s=s+i;
157 }
158 printf("s=%d\n",s);
159 }
160 //---------------------------------10
161 #include<stdio.h>
162 void main()
163 {
164 int i,n,t=1;
165 printf("Enter n:");
166 scanf("%d",&n);
167 for(i=1;i<=n;i++)
168 {
169 t=t*i;
170 }
171 printf("t=%d\n",t);
172 }
173 //------------------------------------11
174 #include<stdio.h>
175 void main()
176 {
177 int i,k,n;
178 printf("Enter n?");
179 scanf("%d",&n);
180 k=n-1;
181 for(i=2;i<=k;i++)
182 {
183 if(n%i==0)
184 break;
185 }
186 if(i>k)
187 printf("%d is 素数\n",n);
188 else
189 {
190 printf("%d not is 素数\n",n);
191 }
