Why is there a segmentation fault in the code below - c

Question

First we are reading from the files and forming arrays, then we are calculating hanning window(hanning fn) for each array sample , finally we are multiplying(mul fn) the array and the hanning window to form the array final.
#include <stdio.h>
#include<math.h>
#include <stdlib.h>
#include </usr/local/src/libsndfile-1.0.25/libsndfile-1.0.25/src/sndfile.h>
#include </usr/local/src/libsndfile-1.0.25/libsndfile- 1.0.25/src/sndfile.h.in>
void hanning(int);
float w[256];
float mul(float*,int*,float*,float*,int);
int main()
{
SNDFILE *sf1,*sf2,*sf3,*sf4,*sf5,*sout;
SF_INFO info1,info2,info3,info4,info5,infout;
int num_channels;
int num_items1,num_items2,num_items3,num_items4,num_items5;
int num1,num2,num3,num4,num5;
int *buf1,*buf2,*buf3,*buf4,*buf5;
int f1,f2,f3,f4,f5;
int sr1,sr2,sr3,sr4,sr5;
int c1,c2,c3,c4,c5,d;
int i,j=0,N=128,k=0;
float t[128],w1[64],w2[64];
// FILE *out;
hanning(N);
/* Open the WAV file. */
info1.format = 0;
info2.format=0;
info3.format=0;
info3.format=0;
info4.format=0;
info5.format=0;
sf1 = sf_open("/mnt/usb2/voice/a.wav",SFM_READ,&info1);
sf2 = sf_open("/mnt/usb2/voice/na1.wav",SFM_READ,&info2);
sf3 = sf_open("/mnt/usb2/voice/ma.wav",SFM_READ,&info3);
sf4 = sf_open("/mnt/usb2/voice/ra__.wav",SFM_READ,&info4);
sf5 = sf_open("/mnt/usb2/voice/ttha.wav",SFM_READ,&info5);
if (sf1 == NULL)
{
printf("Failed to open the file.\n");
exit(-1);
}
/* Print some of the info, and figure out how much data to read. */
c1 = info1.channels;
c2 = info2.channels;
c3 = info3.channels;
c4 = info4.channels;
c5 = info5.channels;
f1 = info1.frames;
f2 = info2.frames;
f3 = info3.frames;
f4 = info4.frames;
f5 = info5.frames;
sr1 = info2.samplerate;
sr2 = info2.samplerate;
sr3 = info3.samplerate;
sr4 = info4.samplerate;
sr5 = info5.samplerate;
// printf("frames=%d\n",f);
// printf("samplerate=%d\n",sr);
//printf("channels=%d\n",c);
num_items1 = f1*c1;
num_items2 = f2*c2;
num_items3 = f3*c3;
num_items4 = f4*c4;
num_items5 = f5*c5;
//printf("num_items=%d\n",num_items);
/* Allocate space for the data to be read, then read it. */
buf1 = (int *) malloc(num_items1*sizeof(int));
buf2 = (int *) malloc(num_items2*sizeof(int));
buf3 = (int *) malloc(num_items3*sizeof(int));
buf4 = (int *) malloc(num_items4*sizeof(int));
buf5 = (int *) malloc(num_items5*sizeof(int));
num1 = sf_read_int(sf1,buf1,num_items1);
num2 = sf_read_int(sf2,buf2,num_items2);
num3 = sf_read_int(sf3,buf3,num_items3);
num4 = sf_read_int(sf4,buf4,num_items4);
num5 = sf_read_int(sf5,buf5,num_items5);
for(i=0;i<128;i++)
{
if(i<64){
w1[j]=t[i];
j++;}
else{
w2[k]=t[i];
k++;}
}
x1 = (float *) malloc(num_items1*sizeof(float));
x2 = (float *) malloc(num_items2*sizeof(float));
x3 = (float *) malloc(num_items3*sizeof(float));
x4 = (float *) malloc(num_items4*sizeof(float));
x5 = (float *) malloc(num_items5*sizeof(float));
mul(x1,buf1,w1,w2,num_items1);
mul(x2,buf2,w1,w2,num_items2);
mul(x3,buf3,w1,w2,num_items3);
mul(x4,buf4,w1,w2,num_items4);
mul(x5,buf5,w1,w2,num_items5);
//printf("num=%d\n",num);
sf_close(sf1);
sf_close(sf2);
sf_close(sf3);
sf_close(sf4);
sf_close(sf5);
d=num_items1+num_items2+num_items3+num_items4+num_items5;
final = (float *) malloc(d*sizeof(float));
for(j=0;j<num_items1;j++){
final[i]=x1[j];
i++;}
for(j=0;j<num_items1;j++){
final[i]=x1[j];
i++;}
for(j=0;j<num_items1;j++){
final[i]=x1[j];
i++;}
for(j=0;j<num_items3;j++){
final[i]=x3[j];
i++;}
for(j=0;j<num_items4;j++){
final[i]=x4[j];
i++;}
for(j=0;j<num_items1;i++){
final[i]=x1[j];
i++;}
for(j=0;j<num_items5;j++){
final[i]=x5[j];
i++;}
//sout=sf_open(final,SFM_READ,&infout);
// printf("Read %d items\n",num);
/* Write the data to filedata.out. */
/* out = fopen("filedata.txt","w");
if(out==NULL)
{ printf("Error!");
exit(1); }
printf("a");
for (i = 0; i < 100; i++)
{
fprintf(out,"%d ",final[i]);
fprintf(out,"/n");
}
fclose(out);*/
return 0;
}
void hanning(int N)
{
int half, i, idx, n,j=0,k=0;
float PI=3.1428;
// w = (float*) calloc(N, sizeof(float));
// memset(w, 0, N*sizeof(float));
n = N;
if(n%2==0)
{
half = n/2;
for(i=0; i<half; i++)//Calculates Hanning window samples.
{w[i] = 0.5 * (1 - cos(2*PI*(i+1) / (n+1)));
printf("%f\n",w[i]);}
idx = half-1;
for(i=half; i<n; i++) {
w[i] = w[idx];
printf("%f\n",w[i]);
idx--;
}
}
else
{
half = (n+1)/2;
for(i=0; i<half; i++) //Calculates Hanning window for samples
w[i] = 0.5 * (1 - cos(2*PI*(i+1) / (n+1)));
printf("%f\n",w[i]);
}
}
float mul(float *x,int *buf,float *w1,float *w2,int k)/*multiplication of hanning window and array*/
{
float final_1[k],final_2[k];
int i;
for(i=0;i<k;i++){
if(i<64)
final_1[i]=w1[i];
else
final_1[i]=1;}
for(i=0;i<k;i++){
if(i<k-64)
final_2[i]=1;
else
final_2[i]=w2[i];
}
for(i=0;i<k;i++){
x[i]=final_1[i]*final_2[i]*buf[i];
printf("%f\n",x[i]);
}
}

Answer 1

You should initialize your loop variables closer to the actual loops:
There is a missing i=0; after final = (float *) malloc(d*sizeof(float));
This is definitely a bug, but there are other ones: the size you allocate for the final array is probably too small for the copies you make into it: 4 copies of x1, one copy of x3, x4 and x5, but none of x2 (probably a copy/paste bug here).
Also consider using double instead of float for better accuracy in these computations and use M_PI from <math.h> instead of hard coding a very inaccurate value for pi.
Also try and indent your code more consistently, use K&R style for improved readability.