How to use sizeof to determine the number of bytes in C language?

2 years ago
Benjamin Taylor
1 minute

In the C language, the sizeof operator can be used to calculate the number of bytes occupied by a data type or variable. The usage of the sizeof operator is as follows:

sizeof(type)

In this case, type can be a data type or a variable. For example, to calculate the number of bytes occupied by an int type, you can use the following code:

#include <stdio.h>

int main() {
    int size = sizeof(int);
    printf("int类型所占字节数：%d\n", size);
    return 0;
}

The output is:

int类型所占字节数：4

Similarly, you can also use the sizeof operator to calculate the number of bytes occupied by a variable. For example:

#include <stdio.h>

int main() {
    int num = 10;
    int size = sizeof(num);
    printf("num变量所占字节数：%d\n", size);
    return 0;
}

The result is:

num变量所占字节数：4

It should be noted that the sizeof operator returns a value of type size_t, which is typically an unsigned integer.

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