String Compare issues in 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

#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 2

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 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;
}