C语言学习笔记

C语言程序设计

求100-500的质数

#include <stdio.h>

int main()
{
    int i,j,n,f=1;
    for(i=100;i<=500;i++){
        f=1;
        for(j=2;j<i/2;j++){
           if(i%j==0){
              f=0;
           }
        }
        if(f==1){
            printf("%d是质数\n",i);
        }else{
            printf("%d不是质数\n",i);
        }
    }
    return(0);
}

C语言出租车计费

出租车计费问题。起步价10元 (三公里内)，3~ 10公里之间的每公里2.1元，超出10公里部分每公里3元。输入行车里程，得出总费用。

#include<stdio.h>
int main(){
    int a = 0;
    float b = 0.0;
    while(a <= 0){
        printf("Please input a:\n");
        scanf("%d",&a);
        if(a>0 && a <= 3){
            b = 10.0;
        }else if(a>3 && a <= 10){
            b = 10.0 + (a - 3) * 2.1;
        }else if(a>10){
            b = 10.0 + 2.1*7+ (a - 10) * 3.0;
        }else{
            printf("输入错误，请重新输入\n");
        }
    }
    printf("费用为 %f\n",b);
    return 0;
}

C语言基本运算

#include <stdlib.h>
int main()
{
    int a = 100;
    printf("%d\n",a++);//先用后加；100
    printf("%d\n",a);  //先加后用；101
    printf("%d\n",++a);//先加后用；102
    printf("%d\n",-a++);//先用后加；-102
    printf("%d\n",a);  //先加后用；103
    printf("%d\n",a=5);//即时赋值；5
    printf("%d\n",a=(6,6+a,8-a));//及时赋值；8-5=3
    return(0);
}

水仙花程序

#include <stdio.h>
void main()
{
    int i,j,k;
    for(i=0;i<=9;i++)
    {
        for(j=0;j<=9;j++)
        {
            for(k=0;k<=9;k++)
            {
                if(i*i*i + j*j*j + k*k*k == i*100+j*10+k)
                {
                    printf("%d %d %d \n",i,j,k);
                }
            }
        }
    }
}

指针基础

#include <stdio.h> 
int main()
{
    int a = 100;
    int *p = &a;
    printf("%d \n",&a);
    printf("%d",*p);
    return(0);
}

递归调用（迭代）求a的阶乘

#include <stdio.h>
int fib(int b)
{
    int m=1;
    if(b>1)
    {
        m=fib(b-1);
    }
    return b*m;
}
int main()
{
    int a = 6;
    printf("%d \n",fib(a));
    return(0);
}

冒泡排序法求10个数字的排序

#include <stdio.h>
void main()
{
    int arr[10] = {9,8,7,6,5,4,3,2,1,0};
    int temp;
    for(int i=0;i<9;i++)
    {
        for(int j=0;j<9-i;j++)
        {
            if(arr[j] > arr[j+1])
            {
                temp = arr[j];
                arr[j] = arr[j+1];
                arr[j+1] = temp;
            }
        }
        for(int k = 0;k<=9;k++)
        {
            printf("%d,",arr[k]);
        }
        printf("\n");
    }
}

8,7,6,5,4,3,2,1,0,9,
7,6,5,4,3,2,1,0,8,9,
6,5,4,3,2,1,0,7,8,9,
5,4,3,2,1,0,6,7,8,9,
4,3,2,1,0,5,6,7,8,9,
3,2,1,0,4,5,6,7,8,9,
2,1,0,3,4,5,6,7,8,9,
1,0,2,3,4,5,6,7,8,9,
0,1,2,3,4,5,6,7,8,9,

选择排序

#include <stdio.h>
 
void main()
{
    int a[10]={18,12,10,84,30,16,78,9,21,38};
    int i,j,k,temp;
    for(i=0;i<10;i++)
    {
        printf("%d\t",a[i]);
    }
    printf("\n");
    for(i=0;i<10;i++)
    {
        k=i;
        for(j=i+1;j<10;j++)
        {
            if(a[k]>a[j]) k=j;
        }
        if(i!=k){
            temp=a[i];
            a[i]=a[k];
            a[k]=temp;
            //printf("%d和%d交换\n",a[i],a[k]);
        }
        for(int m=0;m<10;m++)
        {
            printf("%d\t",a[m]);
        }
        printf("\n");
    }
}

输出菱形图案

#include <stdio.h>
void main()
{
    int line=3;
    for(int i=1;i<=line;i++)
    {
        for(int j=line-i;j>0;j--)
        {
            printf("-");
        }
        for(int j=1;j<=i*2-1;j++)
        {
            printf("*");
        }
        printf("\n");
    }

    for(int i=line+1;i<=line*2-1;i++)
    {
        for(int j=1;j<i-line+1;j++)
        {
            printf("-");
        }
        for(int j=line*4-i*2-1;j>=1;j--)
        {
            printf("*");
        }
        printf("\n");
    }
}

--*
-***
*****
-***
--*

函数返回数组

#include <stdio.h>
int* arrs(int* b)
{
    //在这里排序好
    return b;
}
void main()
{
    int a[] = {1,2,34,5};
    int* c;
    c = arrs(a);
    for(int i=0;i<=3;i++)
    {
        printf("%d \n",c[i]);
    }
}

VB程序设计

字符串处理

Dim s As String
s = "abcdefg"
Print Right(s, 3)  'efg
Print Left(s, 3)   'abc
Print Mid(s, 3, 2) 'cd
If "a" < "b" Then
    Print "真"
End If

If "caaaaa" < "d" Then
    Print "真"
End If

Private Sub Command1_Click()
    Dim x As Double
    Dim n As Integer
    Dim n As Boolbean
    Dim name As String * 20
    x = 13000000000
    n = 0
    Do While x <= 2600000000
        x = x*1.008
        n = n+1
    Loop
    If n >= 1 Then
        Print "___"
    Else
        Print "___"
    End If

    Dim i As Integer
    Dim j As Integer
    For i = 0 To 5
        Print "___"
    Next
    For i = 1 To 9
        For j = 1 To i
            S = i & "*" & j & "=" & i * j
            Print Tab((j - 1) * 9); S;
        Next j
        Print ""
    Next i

    For i = 1 To 20 Step 2
        Print i
    Next i

    Select Case d
        Case 1
            Print "___"
        Case 2
            Print "___"
        Case 3
            Print "___"
        Case else
            Print "___"
    End Select
    Dim n As Integer
    n = InputBox("请输入要判断的年份")
    If n Mod 4 = 0 And n Mod 100 <>0 Or n Mod 400 = 0 Then
        MsgBox "是闰年"
    Else
        MsgBox "不是闰年"
    End If
End Sub

VB的选择排序

Private Sub Command1_Click()
    Dim d(20) As Single
    n = Val(InputBox("请输入数据的总数里"))
    
    For i = 1 To n
        d(i) = Val(InputBox("请输入第" & i & "个数据"))
    Next i
    
    For t = 1 To n
        Print d(t)
    Next t
    
    For i = 1 To n - 1
        Min = d(i):
        m = i
        For j = i + 1 To n
            If d(j) < Min Then
                Min = d(j)
                m = j
            End If
        Next j
        
        If d(i) <> d(m) Then
            Print "交换" & d(i) & "和" & d(m)
            k = d(i)
            d(i) = Min
            d(m) = k
            For t = 1 To n
                Print d(t)
            Next t
        End If
    Next i
End Sub

生成20个10-100的随机数然后统计5的整数倍的和

Private Sub Command1_Click()
    Dim m As Integer
    Dim sum As Integer    
    sum = 0
    For m = 1 To 20
        x = Int(10 + Rnd * 91)
        If x Mod 5 = 0 Then
            Print x
            sum = sum + x
        End If
    Next m
    Print "sum="; sum
End Sub

Python语言备考

print(11//4) #整除得2
print(10**4) #10的4次方

for index in range(6):
    print(index) #输出0到5
for index in range(6,10):
    print(index) #输出6到9

print(4<=5<=6<=7) #输出True
print(4<=5<=6>=7) #输出False
print(len('R\0S\0T')) #输出5

d={"大海":"蓝色","天空":"灰色","大地":"黑色"}
print(d["大地"])            #黑色
print(d.get("天空","黄色")) #灰色
print(d.get("学校","黄色")) #黄色

a=[1,2,3]
print(id(a))
a.append(4)
print(a)
print(id(a))