printf() function in C++

In this guide, you will learn what is printf() function is in C++ programming and how to use it with an example.

1. printf() Function Overview

The printf() function is a part of the <cstdio> library in C++. It is used to print formatted data to the standard output. The function interprets the format string and formats the subsequent arguments accordingly, then outputs the resulting string.

Signature:

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

Parameters:

- format: A string that contains text and format specifiers, which define the expected data types for the subsequent arguments.

- ...: Variable number of arguments to be formatted and printed according to the format string.

2. Source Code Example

#include <iostream>
#include <cstdio>

int main() {
    int age = 25;
    const char* name = "JohnDoe";

    // Print formatted data to the standard output
    printf("Name: %s\nAge: %d\n", name, age);

    double pi = 3.14159;
    printf("Value of Pi up to 3 decimal places: %.3f\n", pi);

    return 0;
}

Output:

Name: JohnDoe
Age: 25
Value of Pi up to 3 decimal places: 3.142

3. Explanation

1. We define an integer age and a string name.

2. The printf() function is then used to print these values in a formatted manner to the standard output. The %s format specifier is used for the string name, and the %d format specifier is used for the integer age.

3. We further use printf() to print the value of pi up to 3 decimal places. The format specifier %.3f indicates that the floating-point number should be printed with a precision of three decimal places.