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。

#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

#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