learn through sufferingC Language

learn through sufferingC Language

Use the abs function to calculate the absolute value.
Please note that you need to include `` to use the `abs` function.

キーワード

【absolute value】

数直線上における原点からの距離。
要するに、正の値はそのまま、負の値は正にしたnumerics。

The following is how to use the abs function.

abs function

exponent = pow(numerics, 指数);

The following program is an example of calculating absolute value.

Source code

#include <stdio.h>
#include <stdlib.h>

void main(void)
{
    printf("%d\n", abs(10));
    printf("%d\n", abs(-10));

    return;
}

The output of this program is as follows:

Execution results

10
10

To calculate exponents, use the pow function.
Please note that you need to include `` to use the pow function.

The pow function is used as follows:
Please note that the value will be a double type, so storing it as an integer will result in inaccuracy.

pow function

#include <stdio.h>
#include <stdlib.h>

void main(void)
{
    printf("%d\n", abs(10));
    printf("%d\n", abs(-10));

    return;
}

The following program is an example of calculating exponents.

Source code

#include <math.h>
#include <stdio.h>

void main(void)
{
    printf("%dの%d乗 = %f\n", 5, 2, pow(5, 2));
    printf("%dの%d乗 = %f\n", 8, 3, pow(8, 3));
    printf("%dの%d乗 = %f\n", 2, 10, pow(2, 10));

    return;
}

The output of this program is as follows:

Execution results

5の2乗 = 25.000000
8の3乗 = 512.000000
2の10乗 = 1024.000000

To calculate a square root, use the sqrt function.
Please note that you need to include `` to use the sqrt function.

キーワード

【square root】

2乗するとその数になるnumerics。
元のnumericsを正方形の面積とすると、square rootは辺の長さに当たる。

The following is how to use the sqrt function.
Please note that the value will be a double type, so storing it as an integer will result in inaccuracy.

sqrt function

square root = sqrt(numerics);

The following program is an example of calculating a square root.

Source code

#include <math.h>
#include <stdio.h>

void main(void)
{
    printf("√%d = %f : %f * %f = %f\n", 100, sqrt(100), sqrt(100), sqrt(100), sqrt(100) * sqrt(100));
    printf("√%d = %f : %f * %f = %f\n", 2, sqrt(2), sqrt(2), sqrt(2), sqrt(2) * sqrt(2));

    return;
}

The output of this program is as follows:

Execution results

√100 = 10.000000 : 10.000000 * 10.000000 = 100.000000
√2 = 1.414214 : 1.414214 * 1.414214 = 2.000000

"It looks like the calculations are accurate because of rounding."
Caution is needed because repeating similar calculations will result in error.

"Use the following functions to calculate trigonometric functions."
Note that you need to include <math.h> to use these functions.

function名	Trigonometric functions値
sin	サイン
cos	コサイン
tan	タンジェント
asin	アークサイン
acos	アークコサイン
atan	アークタンジェント

Since all of these functions work in the same way, I will use the tan function as an example from now on.
Here's how to use the tan function.


However, this angle is not the 90 degrees that we typically use as a right angle.
We use a unit of angle called radians.
You can convert from degrees to radians using the following formula.




It's tedious to perform this calculation every time, so I'm creating a macro like this.


The following program calculates the angle of elevation when a person with a height of 160cm looks up at a tree from a distance of 5 meters.
Here's an example of finding the height of the tree when the angle is 40 degrees.


The output of this program is as follows:


Because trigonometric function calculations also produce errors if repeated, caution is needed.