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2.0 KiB
C++

/*-------------- EULER'S METHOD TO SOLVE DIFFERENTIAL EQUATION --------*/
/* THIS PROGRAM CALCULATES THE VALUE y AT GIVEN VALUE OF x
USING EULER'S METHOD. THE FUNCTION y' = f(x,y) IS
DEFINED IN THE PROGRAM.
y' = x - y
Hence f(x,y) = x - y
INPUTS : 1) Initial values of x and y.
2) Step size h.
OUTPUTS : Calculated values of y at every step. */
/*------------------------------ PROGRAM --------------------------*/
#include<stdio.h>
#include<math.h>
#include<stdlib.h>
#include<conio.h>
void main()
{
double f (double x0,double y0); /* DECLARATION OF A FUNCTION f */
double y0,y1,x0,x1,h,x;
int i,n,t;
clrscr();
printf("\n EULER'S METHOD TO SOLVE DIFFERENTIAL EQUATION\n");
printf("\n\nEnter x0 = ");
scanf("%lf",&x0); /* ENTER VALUE OF x0 */
printf("\n\nEnter y0 = ");
scanf("%lf",&y0); /* ENTER VALUE OF y0 */
printf("\n\nEnter the value of x at which y is to be found = ");
scanf("%lf",&x); /* ENTER VALUE OF x */
printf("\n\nEnter the value of h = ");
scanf("%lf",&h); /* ENTER THE VALUE OF h */
i = 0;
printf("\nPress any key to see step be step display of results...\n");
while(x0 < x) /* LOOP TO CALCULATE y USING EULER'S FORMULA */
{
i++;
x1 = x0 + h;
y1 = y0 + h * f(x0,y0); /* IMPLEMENTATION OF EULER'S FORMULA */
printf("\nx%d = %lf y%d = %lf",i,x1,i,y1);
x0 = x1;
y0 = y1;
getch();
}
}
/*---------------------------------------------------------------------*/
double f ( double x,double y) /* FUNCTION TO CALCULATE VALUE OF f(x,y)*/
{
double y_dash;
y_dash = x - y; /* function f(x,y) = y' = x - y */
return(y_dash);
}
/*------------------------ END OF PROGRAM -----------------------------*/