How to use printf in c++

The printf() function is a C standard library function used to output formatted data to a terminal or file. It contains a format string that specifies the output format and allows passing a variable number of arguments to provide the actual data. Format strings use format specifiers to specify the format and alignment of data types. Common types include integers (%d), floats (%f), characters (%c), and strings (%s). printf() writes formatted output to the terminal or file based on a format string and supplied data, and returns the number of characters successfully output.

Usage of printf() function in C

What is printf() function?

printf() is a standard input and output library function in C, used to output formatted data to the terminal or file.

Syntax:

<code class="cpp">int printf(const char *format, ...);</code>

Among them:

• format: Format string, specify the format of the output content .
• ...: A variable number of parameters that provide the data to be output in the order of the types specified in the format string.

Format string:

The format string consists of the following elements:

• Normal characters: output as is.
• Format specifier: Starting with a percent sign %, specify the format and alignment of the data type.

Format specifier syntax:

<code>% [flags] [width] [.precision] type</code>

Among them:

• flags: Optional flags , specify alignment, padding, and symbols.
• width: Optional field width, specifying the minimum width of the output.
• precision: Optional precision, specifying the number of decimal places or string length.
• type: Required data type specifier, specifying the output data type.

Common format specifier types:

##TypeData typeDecimal integerFloating point number##%c%s

%d
%f
Character
String

Example:

<code class="cpp">#include <iostream>

using namespace std;

int main() {
  int age = 25;
  string name = "John";

  // 输出一个格式化的字符串
  printf("Name: %s, Age: %d\n", name.c_str(), age);

  return 0;
}</code>

Output:

<code>Name: John, Age: 25</code>

Tips:

printf()
• is a variadic function that can pass any number of parameters. The data type in the format string must match the provided parameters.
• To avoid buffer overflow, please specify the field width correctly.
• printf()
• Returns the number of characters successfully output.

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