Program does not run without reading the contents of the variable

Question

I am creating a simple program for a college job, which reads 2 numbers, an arithmetic operator and returns the result of that operation. But it turns out that after printing on the screen "type the operator", the program does not wait for me to enter the character, but finishes the program. What is the error? follows the code.

#include <stdio.h>
int main() {
    float n1,n2;
    char op;

    printf("Digite o primeiro operando: \n");
    scanf("%f", &n1);

    printf("Digite o segundo operando: \n");
    scanf("%f", &n2);

    printf("Digite um dos operadores aritmeticos (+,-,* ou /): \n");
    scanf("%c", &op);

    if (op == '+')
      printf("%f, %c",n1,op,n2,"=",n1+n2);
    else if (op == '-')
       printf("%f, %c",n1,op,n2,"=",n1-n2);
    else if (op == '*')
        printf("%f, %c",n1,op,n2,"=",n1*n2);
    else if (op == '/') {
        while (n2=0) {
            printf("Digite o divisor não nulo: \n");
            scanf("%f", &n2);
        }
        printf("%f, %c",n1,op,n2,"=",n1/n2);
    }
    else
        printf("Operador invalido! \n");

    return 0;             
}

Answer 1

Cauã, what I did to solve your problem was to put a blank space before the %c

printf("Digite um dos operadores aritmeticos (+,-,* ou /):\n");
scanf(" %c", &op);

For you do not need to use the blank space, you can use the fflush

fflush(stdin);      
printf("Digite um dos operadores aritmeticos (+,-,* ou /):\n"); 
scanf("%c", &op);