#include <stdio.h>
#include <windows.h>
#include <math.h>

void Pos(int x,int y)
{
    COORD pos;
    HANDLE hOutput;
    pos.X = x;
    pos.Y = y;
    hOutput = GetStdHandle(STD_OUTPUT_HANDLE);
    SetConsoleCursorPosition(hOutput, pos);
}

int main()
{
    int n=0;
    double x,y=0.0
 
,result=0.0,a,b;
    system("mode con cols=50 lines=20");
    system("title                                                     求y=x的積分");
    printf("請輸入積分區間 a,b:[   ]");
    Pos(20,0);
    scanf("%lf,",&a);
    Pos(23,0);
    scanf("%lf",&b);
    x=a;
    while(x<b)
    {
        y += x;
        x 
 
+= 0.0001;
        n++;
    }
    result = ( (b-a)/n ) * y;
    Pos(0,2);
    printf("y=x在積分區間[%.2lf,%.2lf]的結果為:%.4lf\n",a,b,result);
    return 0;
}

求x在區間[a,b]上的積分