Updating cooley-tukey.md and small changes to fft.c

Author: Gathros

chapters/FFT/code/c/fft.c

@@ -9,12 +9,10 @@
 void dft(double complex *X, const size_t N) {
     double complex tmp[N];
     for (size_t i = 0; i < N; ++i) {
-        double complex sum = 0 + 0 * I;
+        tmp[i] = 0;
         for (size_t j = 0; j < N; ++j) {
-            sum += X[j] * cexp(-2.0 * PI * I * j * i / N);
+            tmp[i] += X[j] * cexp(-2.0 * PI * I * j * i / N);
         }
-
-        tmp[i] = sum;
     }
 
     for (size_t i = 0; i < N; ++i) {

chapters/FFT/cooley_tukey.md

@@ -72,7 +72,7 @@ For some reason, though, putting code to this transformation really helped me fi
 {% sample lang="jl" %}
 [import:2-11, lang:"julia"](code/julia/fft.jl)
 {% sample lang="c" %}
-[import:2-11, lang:"julia"](code/julia/fft.jl)
+[import:9-21, lang:"c_cpp"](code/c/fft.c)
 {% sample lang="cpp" %}
 [import:2-11, lang:"julia"](code/julia/fft.jl)
 {% sample lang="hs" %}
@@ -117,7 +117,7 @@ In the end, the code looks like:
 {% sample lang="jl" %}
 [import:14-31, lang:"julia"](code/julia/fft.jl)
 {% sample lang="c" %}
-[import:9-28, lang:"c_cpp"](code/c/fft.c)
+[import:23-42, lang:"c_cpp"](code/c/fft.c)
 {% sample lang="cpp" %}
 [import:27-57, lang:"c_cpp"](code/c++/fft.cpp)
 {% sample lang="hs" %}