What is the problem in the following program?

I've started to write a new short program to train to handle with files, but I didnt get where the mistake is in my program. Here is the code:

int main(){

    int temp;
    FILE *fp;

    fp = fopen("questions.txt", "r");

    if(fp == NULL){
        printf("Datei konnte NICHT geöffnet werden.\n");
    }else {
        printf("Datei konnte geöffnet werden.\n");
        int a = 0;
        char s[100];
        char s2[100];
        int fragen = 0;
        int rantworten = 0;

        while((temp = fgetc(fp)) != EOF){
            if(temp == '\n'){
                if(a > 0){
                    printf("\n");
                    scanf("%99s", &s2[0]);

                    int b = strcmp(s, s2);

                    if(b == 0){
                        printf("\nRichtige Antwort\n");
                        fragen ++;
                        rantworten++;
                    }else{
                        printf("\nFalsche Antwort\n");
                        fragen++;
                    }
                }
                a++;
            }

            if(a % 2 == 0){
                printf("%c", temp);
            }else {
                strcat(s, temp);
            }

        }
    printf("Von %d Fragen waren %d richtig!", fragen, rantworten);

    fclose(fp);
    }
return 0;
}

and here is the output:

Datei konnte ge÷ffnet werden.
Wie hei├ƒt der h├Âchste Berg?
Process returned -1073741819 (0xC0000005)   execution time : 3.047 s
Press any key to continue.

as you can see is the program do not going into the scanf command.

If you need it here is the textdocument:

Wie heißt der höchste Berg?
Mount Everest
In welchem Jahr erklärten die Vereinigten Staaten von Amerika ihre Unabhängigkeit?
1776

Thank you very much for every answer.