How to use printf in c++

The printf() function is used in C and C to format output data to standard output. It outputs different types of data to the screen in a specified format by using format specifiers (%d, %u, %f, %c, %s). Function syntax: printf(const char *format, ...), where format specifies the format and ... represents a variable number of parameters. It returns the number of characters printed or a negative value on error.

Usage of printf() in C

printf() is a standard library function in C and C. Use For formatting output data to standard output (usually the console). It allows developers to print different types of data to the screen in a controlled manner.

Usage:

The syntax of the printf() function is as follows:

int printf(const char *format, ...);

Among them:

• format : A pointer to a format string that specifies how to format the output data.
• ...: A variable number of arguments, corresponding to placeholders in the format string.

Format options:

The format string uses format specifiers to specify how to output the data type. Common format specifiers include:

• %d: signed decimal integer
• %u: unsigned decimal integer
• %f: double precision floating point number
• %c: character
• %s: string

Example:

The following code example shows how to use the printf() function to print different types of data:

#include <iostream>
#include <cstdio>

int main() {
  int age = 25;
  double gpa = 3.75;
  char grade = 'A';
  std::string name = "John Smith";

  // 打印不同类型的数据
  printf("Name: %s\n", name.c_str());
  printf("Age: %d\n", age);
  printf("GPA: %.2f\n", gpa);
  printf("Grade: %c\n", grade);

  return 0;
}

Output:

<code>Name: John Smith
Age: 25
GPA: 3.75
Grade: A</code>

Note:

• The format specifier must match the data type of the corresponding parameter.
• If the number of fields specified in the format string is less than the actual number of parameters, the extra parameters will be ignored.
• The printf() function returns the number of characters printed, or a negative value if an error occurs.

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