How much memory do data types like bool, char, short, int, long long, float, and double occupy?

The size of built-in data types in C and C++ is not strictly fixed by the standard, except for sizeof(char), which is always 1. Other sizes may vary depending on the processor architecture and compiler. However, there are guaranteed minimum ranges of values and typical sizes on most modern systems (e.g., x86-64):

Data Type	Minimum Range (C/C++)	Typical Size (bytes)
bool	Not explicitly defined by the standard	1
char	Based on a byte (>= 8 bits)	1
short	>= [-32767, +32767] (>= 16 bits)	2
int	>= short (>= 16 bits)	4
long long	>= [-9223372036854775807, +9223372036854775807] (>= 64 bits)	8
float	Single precision (usually IEEE 754)	4
double	Double precision (usually IEEE 754)	8

The actual size can be determined using the sizeof operator:

#include <iostream>

int main() {
    std::cout << "sizeof(bool): " << sizeof(bool) << " bytes" << std::endl;
    std::cout << "sizeof(char): " << sizeof(char) << " bytes" << std::endl;
    std::cout << "sizeof(short): " << sizeof(short) << " bytes" << std::endl;
    std::cout << "sizeof(int): " << sizeof(int) << " bytes" << std::endl;
    std::cout << "sizeof(long long): " << sizeof(long long) << " bytes" << std::endl;
    std::cout << "sizeof(float): " << sizeof(float) << " bytes" << std::endl;
    std::cout << "sizeof(double): " << sizeof(double) << " bytes" << std::endl;
    return 0;
}