c - What is wrong with my implementation for integration using Simpson's Rule -


i creating c program solving integrals using simpsons rule, wrote , runs, after giving program values returns me value definite integral of 0.0000. rechecked every line @ seems well, here's code problem appreciated

#include<stdio.h> #include<math.h> float ad(int a, int b, int n) {     float f4, f2, z, v, q4=0, q2=0, d, m, fa, fb;     int w=2, g=1, k=1, j=1;     z=(b-a)/n;     fa=6*pow(a,2)+16*pow(a,3);     fb=6*pow(b,2)+16*pow(b,3);     f4=6*pow(a+z*w,2)+16*pow(a+z*w,3);     f2=6*pow(a+z*g,2)+16*pow(a+z*g,3);     v=fa+fb;     m=v*z;     while(k<=n/2)     {          q4=q4+(z/3)*(4*f4);         w=w+2;          k++;     }     while(j<=(n-2)/2)     {          q2=q2+(z/3)*(2*f2);         g=g+2;          j++;     }     d=m+q4+q2;     return d; } main() {     int x, y, l;     float o;     printf("enter number x: ");     scanf("%d", &x);     printf("enter number y: ");     scanf("%d", &y);     printf("enter number: ");     scanf("%d", &l);     if(l%2!=0)     {         printf("the number odd!\n");         return 1;      }     o=ad(x, y, l);     printf("the aprox integral es: %f\n", o);     return 0; }

it gives me 2 errors: 

--------------------configuration: mingw5 - cui debug, builder type: mingw--------------------  checking file dependency... compiling e:\anti simpson\ad.cpp... [warning] e:\anti simpson\ad.cpp:29: warning: converting `int' `float' [warning] e:\anti simpson\ad.cpp:50:2: warning: no newline @ end of file linking...  complete make ad: 0 error(s), 2 warning(s) generated e:\anti simpson\ad.exe

you declared function return int, returning float, result is: float returning gets truncated, , int.

i'm guessing integrals had value between 0 , 1, function returned 0

just change int ad(int a, int b, int n) float ad(int a, int b, int n)

edit: z=(b-a)/n; a, b , n ints, won't fractional part in division. try z=(b-a)/(n * 1.0); cast 1 of opreands float fractional part well


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