Hi, Recently I wrote a small program for bit stuffing i.e., I give an input of stream of bits(0,1) and if there are five consecutive 0's then I append a bit 1 and vice versa. It compiled well, but on executing it, there was an SEGMENTATION ERROR. Can anyone please help me in solving the problem. Below is the code I wrote for that program .... #include<stdio.h> #include<string.h> int main() { char *s="",t; int i,j,l,c=0; printf("\n Enter String to be Bit Stuffed : "); scanf("%s",s); t=s[0]; l=strlen(s); for(i=1;s[i]!='\0';i++) { if(t==s[i]) { c++; if(c==4) { for(j=l;j>l;j--) s[j+1]=s[j]; if(s[i]=='0') s[i+1]='1'; else s[i+1]='0'; printf("\n String after Bit Stuffing is %s",s); } else continue; } else { t=s[i]; c=0; continue; } } return 1; } Regards, kolpur