c - 为什么我的 C 程序不能正常工作？

Question

这是我的程序:

int main(){

    struct Koordinaten {
        float x;
        float y;
    }Vektor[3];

    typedef struct Koordinaten Koordinaten;

    float A[3], s, b; 
    for(int i = 0; i < 3; i++){
        char d;
        if(i == 0)
            d = 'A';
        if(i == 1)
            d = 'B';
        if(i == 2)
            d = 'C';

        printf("Please enter the coordinates of the %c vector:\nx: ", d);
        scanf("%f", &Vektor[i].x);
        printf("\ny: ");
        scanf("%f", &Vektor[i].y);

        printf("Values of the %c vector x: %f  y: %f\n\n", d, Vektor[i].x, Vektor[i].y);

        A[i] = sqrt(Vektor[i].x * Vektor[i].x + Vektor[i].y * Vektor[i].y);
        printf("The length of the vector %c is: %f\n\n", d, A[i]);
    }

    s = 1/2 * (A[0] + A[1] + A[2]);
    printf("s = %f\n", s);

    b = sqrt(s * (s - A[0]) * (s - A[1]) * (s-A[2]));
    printf("The area is: %f", b);
}

如您所见，我想取三个 vector 并给出 vector 的面积。由于带有 s 变量的行，它完美地工作。我的程序只给了我 0 的 s 值，但它必须是 7.5!

Answer 1

在你的代码中

  s = 1/2 * (A[0] + A[1] + A[2]);

是相同的

  s = (1/2) * (A[0] + A[1] + A[2]);
      ^^^^^^--------------------------This is an integer division, with a result 0, 
                                      so, 's' will always have a value 0. 

你需要把它改成

 s = 1.0/2 * (A[0] + A[1] + A[2]);
     ^^^^^^-----------------------------now this is floating point division.

以确保浮点除法。