Program is crashing because of scanf_s in Visual Studio Ultimate 2013

Question

I just started a while ago with C language because my University has a few programming lessons. I knew a little of C from High School when we were programming it in Dev C++ program. Now we need to use Visual Studio for it and next program I wrote works fine in Dev C++ but crashes after entering name. In dev C++ I remove _s from strcat and scanf and it works perfect. Can somebody help me with this problem ? This program is about entering a name and it should randomly set you in one of those two teams.

#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>

int main() {
    int maxPlayers = 16, player, teamForming, numPlayer1 = 0, numPlayer2 = 0;
    char blueTeam[256] = "", redTeam[256] = "", name[16];
    for (player = 1; player <= maxPlayers; player++) {
        printf("\nEnter a name of %d. player : ", player);
        scanf_s(" %s", name);
        teamForming = rand() % 2;
        if (teamForming == 0) {
            if (numPlayer1 == 8) {
                strcat_s(redTeam, name);
                strcat_s(redTeam, " ");
                numPlayer2++;
                break;
            }
            strcat_s(blueTeam, name);
            strcat_s(blueTeam, " ");
            numPlayer1++;
        } else {
            if (numPlayer2 == 8) {
                strcat_s(blueTeam, name);
                strcat_s(blueTeam, " ");
                numPlayer1++;
                break;
            }
            strcat_s(redTeam, name);
            strcat_s(redTeam, " ");
            numPlayer2++;
        }
    }
    printf("\nBlue team : %s.\n", blueTeam);
    printf("\nRed team : %s.\n", redTeam);
    return 0;
}

Answer 1

scanf_s and scanf have slightly different semantics: for s and [ formats, you must pass the size of the destination array:

scanf_s(" %s", name, sizeof(name));

Similarly, strcat_s takes as a third argument between the destination array and the source string, the count of elements in the destination array.

Here is a modified version of your code:

#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>

int main(void) {
    int maxPlayers = 16, player, teamForming, numPlayer1 = 0, numPlayer2 = 0;
    char blueTeam[256] = "", redTeam[256] = "", name[16];
    for (player = 1; player <= maxPlayers; player++) {
        printf("\nEnter a name of %d. player : ", player);
        scanf_s(" %s", name, sizeof(name));
        teamForming = rand() % 2;
        if (teamForming == 0) {
            if (numPlayer1 == 8) {
                strcat_s(redTeam, sizeof(redTeam), name);
                strcat_s(redTeam, sizeof(redTeam), " ");
                numPlayer2++;
                break;
            }
            strcat_s(blueTeam, sizeof(blueTeam), name);
            strcat_s(blueTeam, sizeof(blueTeam), " ");
            numPlayer1++;
        } else {
            if (numPlayer2 == 8) {
                strcat_s(blueTeam, sizeof(blueTeam), name);
                strcat_s(blueTeam, sizeof(blueTeam), " ");
                numPlayer1++;
                break;
            }
            strcat_s(redTeam, sizeof(redTeam), name);
            strcat_s(redTeam, sizeof(redTeam), " ");
            numPlayer2++;
        }
    }
    printf("\nBlue team : %s.\n", blueTeam);
    printf("\nRed team : %s.\n", redTeam);
    return 0;
}