Detailed explanation of the difference and usage of * and & in C language

In C language, it is used to dereference a pointer and return the value pointed to; & is used to take an address and return a pointer to the variable. Typically used to access or modify the value pointed to by a pointer; & is typically used to create a pointer or pass a reference.

Detailed explanation of the difference and usage of * and & in C language

In C language, *## There are important differences between the # and & operators that work with pointers.

Operator*(Dereference)

• * Operator is used to dereference a pointer and return The value pointed to by the pointer.
Syntax:
• *ptr, where ptr is a pointer to a variable.

Example:

int *ptr;
int value = 10;
ptr = &value; // 为 ptr 分配 value 的地址
*ptr = 20; // 将 value 的值修改为 20

Operator&(get address)

• & The operator is used to take the address of a variable and return a pointer to the variable.
Syntax:
• &var, where var is a variable.

Example:

int value = 10;
int *ptr = &value; // 为 ptr 分配 value 的地址

Difference

• * Dereference pointer, & get variable address.
• * returns the value pointed to, & returns a pointer to the value.
• & is typically used when creating a pointer variable or passing a reference as a function parameter.
• #* is usually used when accessing or modifying the value pointed to by a pointer.

Practical case

The following is a practical case using the

* and & operators :

#include <stdio.h>

int main() {
    int value = 10;
    int *ptr = &value; // 为 ptr 分配 value 的地址

    // 使用 * 解引用指针并打印值
    printf("Value: %d\n", *ptr);

    // 使用 * 修改指针所指向的值
    *ptr = 20;

    // 再次使用 * 打印修改后的值
    printf("Modified value: %d\n", *ptr);

    return 0;
}

Output:

Value: 10
Modified value: 20

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