Below is my code. When I submit it in UVA they are giving me Presentation error. I want to know the reason. I have tried all possible ways. In my code I use 2D-array to store each word of a sentence. I also want to know the reason for giving presentation error. #include<stdio.h> #include<string.h> int main() { char a[10000],ar[100][10000]; int i,j,k,m,n,l,len[10000],c; freopen("input.txt","r",stdin); while(gets(a)) { k=0; i=0; c=0; for(j=0; ; ++k) { if(a[k]==' ' || a[k]=='\0') { ar[i][j]='\0'; len[i]=c; if(a[k]=='\0') break; i++; j=0; c=0; } else { ar[i][j]=a[k]; c++; j++; } } for(m=0; m<=i; m++) { for(n=(len[m]-1); n>=0; n--) { printf("%c",ar[m][n]); } printf(" "); } printf("\n"); } return 0; }