Usage of float and double in c language

In C language, float and double are the two most commonly used floating point types. They differ in precision and storage space: Precision: float is 6-7 significant digits, double is 15- 16 significant figures. Storage space: float occupies 4 bytes, double occupies 8 bytes. Usage scenarios: float is used in scenarios with low accuracy requirements, and double is used in scenarios with high accuracy requirements. Floating point format: sign bit (1 bit), exponent (8/11 bits), and mantissa (23/52 bits).

Usage of float and double in C language

In C language, float and double are the two most common Commonly used floating point types. They are both floating point numbers in the IEEE 754 standard, but they differ in precision and storage space.

Precision

• The float type uses 32 bits to store floating point values, and the precision is approximately 6-7 significant digits.
• The double type uses 64 bits to store floating point values, with an accuracy of approximately 15-16 significant digits.

Storage space

• The float type occupies 4 bytes of storage space.
• The double type occupies 8 bytes of storage space.

Usage scenarios

Generally speaking, the float type is used to store floating point values ​​that do not require high precision, such as coordinates in GUI or games. Fraction. The double type is used to store floating point values ​​that require high precision, such as amounts in scientific calculations or financial applications.

Floating point format

Floating point value consists of sign bit (1 bit), exponent (8 bits/11 bits) and mantissa (23 bits/52 bits) .

float type:

<code>符号位：1位
指数：8位
尾数：23位</code>

double type:

<code>符号位：1位
指数：11位
尾数：52位</code>

Precision comparison

The following code example demonstrates the difference in precision between float and double types:

<code class="c">#include <stdio.h>

int main() {
    float f = 1.23456789;
    double d = 1.23456789;

    printf("float: %f\n", f);
    printf("double: %f\n", d);

    return 0;
}</code>

Output results:

<code>float: 1.234568
double: 1.2345678900</code>

As you can see, the double type retains more significant digits, so the precision is higher .

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