2019.1.23

1.画余弦函数

#include <stdio.h>
#include <math.h> //本程序中反三角函数的计算用到标准库中的 math.h文件

//编译时出错，在后面加上 -lm即可

int main()
{
    double y; //此处y为浮点型，提高计算精度
    int x;
    int m;
    for(y = 1; y >= -1; y -= 0.1) //y值从1到-1，步长为0.1
    {
        m = acos(y)*10; //计算出y值对应的横坐标m，放大10倍
        for(x = 1; x < m; x++)
        {
            printf(" "); //左半边的空格
        }
        printf("*"); //左半边的*号
        for( ; x < 62 - m; x++)
        {
            printf(" "); //两个星号之间的空格
        }
        printf("*\n"); 最右侧星号后回车
    }
    return 0;
}

2.正弦曲线

#include <stdio.h> //详细分析过程见文章最后的附图
#include <math.h>
#define PAI 3.141592
int main()
{
    double y;
    double x,m;
    double n;
    for(y = 1; y >= 0; y -= 0.1)//x轴上半部分
    {
        m = asin(y)*10;//同理cos，放大十倍
        for(x = 1; x < m; x++)
        {
            printf(" ");
        }
        printf("*");
        for( ; x < 31-m; x++)
        {
            printf(" ");
        }
        printf("*\n");
    }
    for( ; y >= -1; y -= 0.1)//x轴下半部分
    {
        n = asin(-y);
        m = (PAI + n)*10;
        for(x = 1;x < m; x++)
        {
            printf(" ");
        }
        printf("*");
        for( ; x < 94-m; x++)
        {
            printf(" ");
        }
        printf("*\n");
    }
    return 0;
}
 

3.同时绘制正余弦曲线

#include <stdio.h>
#include <math.h>
#define P 3.141592

int main()
{ //定义变量
    int a,b,x;
    double y,n;

//打印x轴上半部分
    for(y = 1; y >= 0; y -= 0.1)
    {
        a = acos(y)*10;
        b = asin(y)*10;
        for(x = 0; x <= 62; x++)
        {
            if(x <= 31)
                if((x == a && x == b) || (x == a && x == (31-b))) printf("+");
                else if(x == a) printf("*");
                       else if(x == b || x == (31-b)) printf("+");
                              else printf(" ");
            else if((x == (62-a) && x == b) || (x == (62-a) && x == (94-b))) printf("+");
                   else if(x == (62-a)) printf("*");
                          else if(x == b || x == (94-b)) printf("+");
                                 else printf(" ");
        }
        printf("\n");
    }

  //打印x轴下半部分 
    for( ; y >= -1; y -= 0.1)
    {
        a = acos(y)*10;
        n = asin(-y);
        b = (P + n)*10;
        for(x = 0; x <= 62; x++)
        {
            if(x <= 31)
                if((x == a && x == b) || (x == a && x == (31-b))) printf("+");
                else if(x == a) printf("*");
                       else if(x == b || x == (31-b)) printf("+");
                              else printf(" ");
            else if((x == (62-a) && x == b) || (x == (62-a) && x == (94-b))) printf("+");
                   else if(x == (62-a)) printf("*");
                          else if(x == b || x == (94-b)) printf("+");
                                 else printf(" ");
        }
        printf("\n");
    }
    return 0;
}