String Compare issues in C - c

Question

So the assignment is this: Problem C: Practice Strings (lastnames.c)(8 points)
Read in n, then n lastnames, and check to see if the first in the list is ever repeated again.
Sample Run #1
Enter n, followed by n Last names (each last name must be a single word):
5 Reagan Bush Clinton Bush Obama
First name in list is not repeated.
Sample Run #2
Enter n, followed by n Last names (each last name must be a single word):
4 Bush Clinton Bush Obama
First name in list is repeated.
I can get the first two names to compare, but I can't figure out how to compare the first to whatever is in the second string array. I don't want to post my code in the event that someone searches this and copies mine. I'll send it to you though. Any help would be greatly appreciated.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void)
{
// initializing character strings
char last[25], first[25];
// initializing number of names, and the index for the number of names
int index, n;
// read in the number
printf("Enter n, followed by n Last names (each last name must be a single word) :\n");
scanf("%d", &n);
scanf("%s", first);
for (index = 0; index < n; index++)
scanf("%s", last);
if (strcmp(last, first)== 0)
{
printf("First name in list is repeated.\n");
}
else
{
printf("First name in list is not repeated.\n");
}
return 0;
}

Answer 1

In your forloop the lastvariable is overwritten every time which means that you are only comparing the first input to the last name in the next sequence of n lastnames.
If you want to count the number of repetitions, use a counter within the for-loop.
int nRepetitions = 0;
/* ... read the numbers and the first string
(therefore index should start with 1)... */
for (index = 1; index < n; index++) {
scanf("%s", last);
if (strcmp(last, first) == 0) {
nRepetitions++;
}
}

Answer 2

#include <stdio.h>
#include <string.h>
int main(void){
char last[25], first[25];
int index, n, repeated = 0;
printf("Enter n, followed by n Last names (each last name must be a single word) :\n");
scanf("%d", &n);
scanf("%s", first);
for(index = 1; index < n; index++){ //index = 1 : aleady input first
scanf("%s", last);
if(strcmp(last, first)== 0)
repeated = 1;
}
if(repeated)
printf("First name in list is repeated.\n");
else
printf("First name in list is not repeated.\n");
return 0;
}

Answer 3

Your code is incorrect..
For loop last has just 1D character array and which is overwritten everytime.
So Use a 2D array instead..
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(void)
{
// initializing character strings
char first[25];
// initializing number of names, and the index for the number of names
int index=0, n;
// read in the number
printf("Enter the number of last names :\n");
scanf("%d", &n);
printf("Enter the first name \n");
scanf("%s", first);
char last[n][25];
for (int i = 0; i < n; i++)
scanf("%s", last[i]);
for(int i=0;i<n;i++)
{
if (strcmp(last[i], first)== 0)
index++;
}
if(index==0)
printf("First name not repeated\n");
else
printf("First name repeated %d times", index);
return 0;
}