问我不明白为什么这段代码给了我乘法，除法和减法的错误结果？

EN

#include <stdio.h>
long operations(char x,int num1 ,int num2 );

int main(void) {
    char x;
    int num1 , num2;
    long result;
    setbuf(stdout,NULL);
    result=operations(x,num1 ,num2 );

}
long operations(char x,int num1 ,int num2 )
{
    printf("please enter your operation sum (1) ,subtrcation(2),mul(3),div(4) :");
    scanf("%d",&x);

    if (x==(1||2||3||4))
    {
    printf("please enter the first and second numbers : \n ");
    scanf ("%d%d" ,&num1 ,&num2);
    }
    else
    {
        printf("error ") ;
    }

    switch (x)
    {
    case 1:
    {
        return  printf("the result  sum is  :%d ",(num1+num2)) ;

    }
    case 2:
    {
        return  printf("the result of subtraction  is :%d ",(num1-num2)) ;

    }
    case 3:
        {
            return  printf("the result multiblication is :%d ",(num1*num2)) ;

        }
    case 4:
        {
            return  printf("the result division  is :%d ",(num1/num2)) ;

        }




    }
}