C language - quadratic equations (root formula)

逻辑概念：

        The format of a quadratic equation is：ax²+bx+c=0(a≠0)

The formula for finding the root is Δ = b²-4×a×c

This program needs to use the header file #include <> among the sqrt()function (math.)。

        The sqrt() function is used to compute a non-negative real numberThe square root of (i.e., the open root sign).

Code Example:

#include <>



#include <>



int main()



{



    float a,b,c,q;



    float x1,x2;



    printf("Please enter the a:");



    scanf("%f",&a);



    printf("Please enter the b:");



    scanf("%f",&b);



    printf("Please enter the c:");



    scanf("%f",&c);



    q = b*b - 4*a*c;



    x1 = (-b+sqrt(q)) / (2*a);



    x2 = (-b-sqrt(q)) / (2*a);



    printf("\n equation is %.1fx² + %.1fx + %.1f = 0\n",a,b,c);



    if(q < 0)



        printf("∵ Δ < 0\n∴ The equation has no solution\n");



    else if(q == 0)



        printf("∵ Δ = 0\n∴ x1=x2=%.2f",x1);



    else




        printf("∵ Δ = %.2f\nOpening the root sign gives %.2f\n∴ x1=%.2f\nx2=%.2f\n",q,sqrt(q),x1,x2);



    return 0;



}

Input Example:

Please enter the a:5




Please enter the b:7




Please enter the c:2

Example output:

Please enter the a:5




Please enter the b:7




Please enter the c:2




 



The equation is5.0x²+7.0x+2.0=0




∵ Δ = 9.00




lit. opening the root sign gets3.00




∴ x1=-0.40




x2=-1.00