Circular Convolution of two sequences using DFT and IDFT

Circular Convolution of  two sequences using DFT and IDFT

Compute the circular convolution of given two sequences using DFT and IDFT.

1:  #include<graphics.h>  
2:  #include<iostream.h>  
3:  #include<conio.h>  
4:  #include<stdlib.h>  
5:  void main(void)  
6:  {  
7:   int sample,impulse,sam[10],imp[10],out[10][10],outp[10]={0},i;  
8:   int gd=DETECT,gm,maxx,maxy,j,k;  
9:   char str[5];  
10:   initgraph(&gd,&gm,"c:\\tc\\bgi");  
11:   maxx=getmaxx();   // Returns maximum x or y screen coordinate  
12:   maxy=getmaxy();  
13:   cout<<"\n\tEnter the number of element in sample sequence::";  
14:   cin>>sample;  
15:   cout<<"\n\tEnter the number of element in impulse sequence::";  
16:   cin>>impulse;           //input impulse & sample sequence  
17:   cout<<"\n\tEnter the sample sequence";  
18:   for(i=0;i<sample;i++)  
19:   cin>>sam[i];  
20:   cout<<"\n\tEnter the impusle sequence";  
21:   for(i=0;i<impulse;i++)  
22:   cin>>imp[i];  
23:   if(sample<impulse)  
24:   for(i=sample;i<impulse;i++)  
25:    sam[i]=0;  
26:   else  
27:   for(i=impulse;i<sample;i++)  
28:    imp[i]=0;  
29:   if(sample<impulse)  
30:        sample=impulse;  
31:   int temp;  
32:   for(i=0;i<sample;i++)  
33:       for(j=0;j<sample;j++)  
34:       {  
35:            out[(j+i)%sample][i]=sam[j];  
36:       }  
37:   for(j=0;j<sample;j++)  
38:    for(k=0;k<sample;k++)  
39:     outp[j]=outp[j]+out[j][k]*imp[k];  
40:   int samp=sample;  
41:   setcolor(RED);  
42:   line(0,maxy/2,maxx,maxy/2);  
43:   line(maxx/2,0,maxx/2,maxy);  
44:   setcolor(GREEN);  
45:   for(i=0;i<samp;i++)  
46:   {  
47:    line(maxx/2+i*30,maxy/2,maxx/2+i*30,maxy/2-outp[i]*5);  
48:    moveto(maxx/2+i*30,maxy/2-outp[i]*5-10);  
49:    itoa(outp[i],str,10);        //converts integer to string  
50:    outtext(str);  
51:   }  
52:   getch();  
53:  }