Not able to take the user input when using if-else and switch case [ C language]

Question

I want someone to run the code, you will find that the code at line number 14 to 17, I don't what this error is. I am giving my code along with this error image.

/*
    A simple calculator made with if-else and switch case
*/

#include <stdio.h>

int main() {
    // if-else
    
    char _opt_1;
    float x_1, x_2;
    
    printf("Enter a valid operator from (+ , - , * , /:  ");
    scanf("%c", &_opt_1);
    
    printf("Enter first number: ");
    scanf("%f", &x_1);
    printf("Enter second number: ");
    scanf("%f", &x_2);
    
    if(_opt_1=='+') {
        printf("The sum is: %f \n", x_1+x_2);
    }else if(_opt_1=='-') {
        printf("The sum is: %f \n", x_1-x_2);
    }else if(_opt_1=='*') {
        printf("The sum is: %f \n", x_1*x_2);
    }else if(_opt_1=='/') {
        printf("The sum is: %f \n", x_1/x_2);
    }else{
        printf("Please enter a valid operator \n");
    }
    
    // switch case
    char operator;
    float x, y;
    
    printf("Enter the operation you want to perform like (+,-,*,/): ");
    scanf("%c", &operator);
    
    printf("Enter the first number: ");
    scanf("%f", &x);
    printf("Enter the second number: ");
    scanf("%f", &y);
    
    switch(operator) {
        case '+':
            printf("The sum is: %f", x + y);
            break;
        case '-':
            printf("The difference is: %f", x - y);
            break;
        case '*':
            printf("The product is: %f", x * y);
            break;
        case '/':
            printf("The division is: %f", x / y);
            break;
        
        default:
            printf("Please enter a valid operator");
    }
    
    return 0;
}