How to output double type in c language

C language output double type method: 1. Use the printf function to output, which can be used to output different types of values, including double types; 2. Use the fprintf function to output to a file. Use the fprintf function to output the double type. Output the value to the specified file; 3. Use the sprintf function to output to a string. Sometimes, you need to output the double type value to a string instead of directly outputting it to the console or file. In this case, you can use sprintf function.

The operating system for this tutorial: Windows 10 system, Code Blocks version 20.03, Dell G3 computer.

C language is a widely used programming language that provides rich data types to meet different programming needs. Among them, the double type is used to represent double-precision floating point numbers, which can store a larger range of values ​​and provide higher precision. In C language, outputting double type values ​​can be achieved in many ways. This article will introduce several commonly used methods.

1. Use printf function to output

The printf function is one of the most commonly used output functions in C language. It can be used to output different types of values, including double. type. When outputting double type, we need to use the format control character "%lf". The following is a simple example:

#include <stdio.h>
int main() {
    double num = 3.14159;
    printf("The value of num is %lf\n", num);
    return 0;
}

In the above example, we define a double type variable num and use the printf function to output its value. Note that the format control character "%lf" is used to output double type values.

2. Use the fprintf function to output to a file

In addition to outputting on the console, C language also provides the function of outputting to a file. Use the fprintf function to output double type values ​​to a specified file. The following is an example:

#include <stdio.h>
int main() {
    double num = 3.14159;
    FILE *file = fopen("output.txt", "w");
    if (file != NULL) {
        fprintf(file, "The value of num is %lf\n", num);
        fclose(file);
    }
    return 0;
}

In the above example, we first use the fopen function to open a file named "output.txt" and assign it to a pointer file pointing to the FILE structure. Then, we use the fprintf function to output the double type value to the file. Finally, the file is closed using the fclose function.

3. Use the sprintf function to output to a string

Sometimes, we need to output a double type value to a string instead of directly outputting it to the control Desk or file. You can use the sprintf function at this time. Here is an example:

#include <stdio.h>
int main() {
    double num = 3.14159;
    char str[20];
    sprintf(str, "The value of num is %lf", num);
    printf("%s\n", str);
    return 0;
}

In the above example, we first define a character array str with a length of 20. Then, use the sprintf function to output the double type value into a string. Finally, use the printf function to output the value of the string.

Summary:

This article introduces several common methods of outputting double types in C language. Through the printf function, we can directly output double type values ​​to the console. Using the fprintf function, we can output double type values ​​to a file. Using the sprintf function, we can output double type values ​​into a string. These methods can meet different output requirements, and developers can choose the appropriate method according to the specific situation.

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