debug horner's rule programme - c++

Question

I am a beginner and totally confused.
I am getting two errors in my c++ code:
Program:32:5: error: redefinition of 'main'
Program:3:6: note: previous definition of 'main' was here
You are given a polynomial of degree n. The polynomial is of the form P(x) = anxn + an-1xn-1 + … + a0. For given values k and m, You are required to find P(k) at the end of the mth iteration of Horner’s rule. The steps involved in the Horner’s rule are given below,
Pn (x) = an
Pn-1 (x) = an-1 + x * Pn (x) 1st iteration.
Pn-2 (x) = an-2 + x * Pn-1 (x) 2nd iteration.
.
.
P0 (x) = a0 + x * P1 (x) nth iteration.
In general, Pi (x) = ai + x * Pi + 1 (x) and P0(x) is the final result. The input to your program is as follows,
Line 1 contains the integers n, m and k separated by space.
Line 2 contains the coefficients an, an-1…, a0 separated by space.
INPUT: Integers n, m, k and the coefficients as described above.
OUTPUT: P(k) value at the end of the mth iteration.
Sample Input:
2 2 5
3 2 1
Sample Output:
86
Constraints:
1 <= n, k, m <= 10
0 <= ai <=10
#include <stdio.h>
#include <string.h>
int main() {
int num, i, j, result, index;
char name[11][11];
char temp[11];
scanf("%d\n", &num);
for(i = 0; i < num; i++)
scanf("%s\n", name[i]);
for(i = 0; i < num; i++) {
index = i;
for(j = i + 1; j < num; j++) {
result = strcmp(name[index], name[j]);
if(result > 0)
index = j;
}
strcpy(temp, name[index]);
strcpy(name[index], name[i]);
strcpy(name[i], temp);
}
for(i = 0; i < num-1; i++) {
printf("%s", name[i]);
printf("\n");
}
printf("%s", name[num-1]);
return 0;
}
#include<stdio.h>
int horner(int [], int, int);
int main()
{
int n, m, k, i;
int a[10];
scanf("%d%d%d",&n,&m,&k);
for (i=0; i<=n; ++i){
scanf("%d",&a[i]);
}
printf("%d",horner(a,m,k));
return 0;
}
int horner(int a[], int m, int k){
if (m==0){
return a[m];
}
else{
return a[m] + k * horner(a,m-1,k);
}
}

Answer 1

The error message seems to have nailed the problem quite well. You've got two main functions. You can only have one, so pick one and delete the other.

Answer 2

Program:32:5: error: redefinition of 'main'
In "Program", line 32, column 5, the identifier main is defined a second time in the same scope.
Program:3:6: note: previous definition of 'main' was here
The first definition was in "Program", line 3, column 6.
There you are. You cannot define the same function twice. There really is nothing to add.
Except perhaps:
Use consistent indentation. Always four spaces is a good rule. Avoid tabulators if you can, they are asking for trouble.
Always put {} around the blocks of if, for, and while, even if they are only one line. Personally, I even add them if the block is empty, adding a // EMPTY comment to make it explicit that the emptiness is not due to a simple typing error.
Whitespace is free. It does not slow down your typing much, and it does make reading the source much easier. You read source much more often than typing it, so do yourself that favor.
Then there's Debugging 101:
Cut away some source that doesn't look as if it's contributing to your problem (which, in this case, is "redefinition of 'main'", not Horner's Rule).
Check if the problem persists.
Cut away MORE source, until you find the ONE change that makes your error go away. Either the problem is now evident to you, or you have found a minimal example to post on something like StackOverflow.
You could have cut away basically everything and end up with:
int main()
{
return 0;
}
int main()
{
return 0;
}
Hmm... what seems to be the problem? Maybe I re-defined 'main()'? ;-)