The difference between * and & in C language

In C language, (asterisk) is used for indirect addressing and value, while & (address character) is used for address and reference. Get the value pointed to by the variable or pointer, used to modify the value and declare the pointer variable; & Get the variable address, used to assign the address to the pointer variable and pass the address as a function parameter.

The difference between * and & in C language

The symbols * and & are different operations in C language Symbols, used for different purposes:

Meaning:

• Asterisk *: indicates indirect addressing or pointer value operation symbol.
• Address character &: represents the address or reference operator.

Purpose:

Asterisk*:

• Get the variable or the variable pointed to by the pointer value.
• Modify the value of a variable or a variable pointed to by a pointer.
• As part of the declaration of the pointer variable.

Address symbol &:

• Get the address (memory location) of the variable.
• Assign the address of the variable to the pointer variable.
• Pass the address of the variable as a function parameter.

Example:

int main() {
    int x = 10;
    int *ptr = &x;  // ptr指向x的地址

    // 获取x的值
    printf("x = %d\n", x);

    // 使用指针获取x的值
    printf("*ptr = %d\n", *ptr);

    // 使用指针修改x的值
    *ptr = 20;
    printf("x = %d\n", x);  // x的值已经改变为20

    return 0;
}

Note:

• *ptr represents the variable pointed to by the pointer variable ptr The value of , and &x represents the address of variable x.
• Normally, a pointer variable is a variable of type "variable type*", pointing to a variable of a specific type.
• Address-taking and indirect addressing operators can be used in combination to implement pointer arithmetic and other advanced data structures.

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