What is the correct way to use printf to print a size_t in C/C++?

We should use "%zu" to print the variables of size_t length. We can use "%d" also to print size_t variables, it may not always produce an error. The correct way to print size_t variables is use of "%zu", because compiler standard %zu is defined as a format specifier for this unsigned type.

Following is the description of "%zu" format:

• z is a length modifier.
• u stands for an unsigned type.

C Example to Print Value of size_t Variable

In this example, we demonstrate a C program that correctly prints a size_t variable:

#include <stdio.h>
#include <stddef.h> // for size_t

int main() {
   size_t count = 100;
   printf("The value of count is %zu\n", count);
   return 0;
}

The above code produces the following result:

The value of count is 100

C++ Example to Print Value of size_t Variable

The following example demonstrates how to print a variable of type size_t in C++:

#include <iostream>
#include <cstdio>    // for printf
#include <cstddef>   // for size_t

int main() {
   size_t count = 100;
   printf("The value of count is %zu\n", count);
   return 0;
}

The above code produces the following result:

The value of count is 100

In conclusion, the program was very simple that uses printf (from the C language) to print a number stored in a size_t variable. Even though its combine C and C++ features to print the value of size_t.