自学教程使用 sizeof 操作符计算int, float, double 和 char四种变量字节大小。
sizeof 是 C 语言的一种单目操作符，如C语言的其他操作符++、--等，它并不是函数。
sizeof 操作符以字节形式给出了其操作数的存储大小。
实例
#include <stdio.h>
int main()
{
int integerType;
float floatType;
double doubleType;
char charType;
// sizeof 操作符用于计算变量的字节大小
printf("Size of int: %ld bytes\n",sizeof(integerType));
printf("Size of float: %ld bytes\n",sizeof(floatType));
printf("Size of double: %ld bytes\n",sizeof(doubleType));
printf("Size of char: %ld byte\n",sizeof(charType));
return 0;
}运行结果：
Size of int: 4 bytes Size of float: 4 bytes Size of double: 8 bytes Size of char: 1 byte
计算 long long, long double 字节大小
实例
#include <stdio.h>
int main()
{
int a;
long b;
long long c;
double e;
long double f;
printf("Size of int = %ld bytes \n", sizeof(a));
printf("Size of long = %ld bytes\n", sizeof(b));
printf("Size of long long = %ld bytes\n", sizeof(c));
printf("Size of double = %ld bytes\n", sizeof(e));
printf("Size of long double = %ld bytes\n", sizeof(f));
return 0;
}运行结果：
Size of int = 4 bytes Size of long = 8 bytes Size of long long = 8 bytes Size of double = 8 bytes Size of long double = 16 bytes