How to keep items in my array in whole program?-CodePudding

Basically in my program, I am using a for loop, it assigns values to each element of the array and stores them in it and then writes them out and it gives good results. However, when I exit the loop and want to write out the elements of this array I get wrong results all equal to 0.0000. How do I overcome this and keep the results outside of the for loop ?

   // declares arrays of the given size
double array[50];

// I calculate the length of the array using sizeof
double array_lenght = sizeof(array) / sizeof(array[0]);
printf("%lf \n", array_lenght);

//declares two variables of type double one for the area over which it will generate x the other for incrementing the deltaX difference
double length;
double deltaX;

// I count the differences of the domains and the value of one sample for x and display it

length = Dmax - Dmin;
deltaX = length / 50;

printf("Delta x =  %lf \n", deltaX);

double i;
for(i = Dmin; i < Dmax; i =deltaX)
{
    // assigns to each element in the array the value of x increased by delta x and stores them in my array.
    int k = 0;
    array[k] = i;
    double y = A * cos(i/B)   C * sin(i)   D;
    printf("For a sample of %lf, the assigned function is %lf \n", array[k], y);
    k  ;
}
    
printf("Elements of original array: \n");    
for (int i = 0; i < array_length; i  ) {     
    printf("%lf ", array[i]);    
}

CodePudding user response：

You're writing to the same array element (element 0) over and over again:

double i;
for(i = Dmin; i < Dmax; i =deltaX)
{
    // assigns to each element in the array the value of x increased by delta x and stores them in my array.
    int k = 0;
    array[k] = i;
    double y = A * cos(i/B)   C * sin(i)   D;
    printf("For a sample of %lf, the assigned function is %lf \n", array[k], y);
    k  ;
}

The initializer for k sets k to 0 on each loop iteration. Just move it outside the loop:

double i;
int k = 0;
for(i = Dmin; i < Dmax; i =deltaX)
{
    // assigns to each element in the array the value of x increased by delta x and stores them in my array.
    array[k] = i;
    double y = A * cos(i/B)   C * sin(i)   D;
    printf("For a sample of %lf, the assigned function is %lf \n", array[k], y);
    k  ;
}

That way it will step through the array as intended.

CodePudding user response：

I think you misplaced your k declaration.

double i;
int k = 0; // <--- moved outside of the loop
for(i = Dmin; i < Dmax; i =deltaX)
{
    //int k = 0; <--- keeps resetting k
    array[k] = i;
    double y = A * cos(i/B)   C * sin(i)   D;
    printf("For a sample of %lf, the assigned function is %lf \n", array[k], y);
    k  ;
}