Why CE with this code?

#include <stdio.h>

int main() {
    float PI = 3.1415926535;
    float squareSize;
    scanf("%f", &squareSize);
    squareSize /= 2;
    int rope;
    scanf("%i", &rope);
    float diagonal;
    diagonal = sqrt((double) (2 * squareSize * squareSize));
    double area;
    if (rope <= squareSize)
        printf("%1.3f", (rope * rope * PI));
    else {
         if (rope >= diagonal)
            printf("%1.3f", (squareSize * squareSize));
         else {
              area = 8 * (squareSize * sqrt((double) (rope * rope - squareSize * squareSize))/2
                        + rope*rope/2 * (PI/4 - acos( (double) (squareSize / rope))));
              printf("%1.3f", area);
         }
    }
    return 0;
}