46 lines
950 B
C
46 lines
950 B
C
|
#include <stdio.h>
|
||
|
|
#include <math.h>
|
||
|
|
|
||
|
|
typedef float(*function)(float);
|
||
|
|
|
||
|
|
//(-2, -1.5) (-1.5, -1) (-1, -0.5) (-0.5, 0)
|
||
|
|
float f(float x) {
|
||
|
|
return 8*x*x*x*x + 32*x*x*x + 40*x*x + 16*x + 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
float testf(float x){
|
||
|
|
return 2;
|
||
|
|
}
|
||
|
|
|
||
|
|
float calcIntegralSquare(float xl, float xr, size_t n, function f) {
|
||
|
|
float sum = 0;
|
||
|
|
float h = (xr-xl)/n;
|
||
|
|
for(size_t i=0; i<n; i++) {
|
||
|
|
sum += f(xl);
|
||
|
|
xl += h;
|
||
|
|
}
|
||
|
|
return sum*h;
|
||
|
|
}
|
||
|
|
|
||
|
|
float calcIntegralTrap(float xl, float xr, size_t n, function f) {
|
||
|
|
float sum = 0;
|
||
|
|
float h = (xr-xl)/n;
|
||
|
|
for(float x=xl+h; x<xr-h; x+=h) {
|
||
|
|
sum += 0.5*h*(f(x)+f(x+h));
|
||
|
|
}
|
||
|
|
return sum;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
int main()
|
||
|
|
{
|
||
|
|
printf("calcIntegralSquare integral %f\n", calcIntegralSquare(0,2,1000,testf));
|
||
|
|
printf("calcIntegralSquare = %f\n", calcIntegralSquare(-1.382683,-0.617316,1000,f));
|
||
|
|
printf("calcIntegralTrap = %f\n", calcIntegralTrap(-1.382683,-0.617316,1000,f));
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|