Coding a irc poker

Question

i'm coding a poker game for irc. This is a piece of the code, it prints the array of cards, and then the value of each card. The array is printed correctly, but a segment violation appears before the value of cards is printed.

Can someone help me with this? Suggestions for optimize the code are accepted too ;P

void barajar() {
srand(time(NULL));

for(i = 0 ; i < 52 ; i++) {
    cartas[i] = i;
}

for(i = 0 ; i < 100 ; i++) {
    int i1 = rand()%52;
    int i2 = rand()%52;
    int tmp = cartas[i1];
    cartas[i1] = cartas[i2];
    cartas[i2] = tmp;
}

for(i = 0 ; i < 51 ; i++) {
    printf("%d, ", cartas[i]);
}
i++;
printf("%d.\n", cartas[i]);
}


int main() {
barajar();
int olol;
for ( olol = 0; olol <=52; olol++ ) {
    int numero = cartas[c];
    int cnum = numero % 13;
    int numero1;

    switch(cnum) {
    case 0:
        nombre1 = "As";
        break;
    case 10:
        nombre1 = "J";
        break;
    case 11:
        nombre1 = "Q";
        break;
    case 12:
        nombre1 = "K";
        break;
    default:
            numero1 = cnum + 1;
        break;
    }
    int opera = numero / 13;
    switch ( opera ) {
        case 0:
            nombre2 = "diamantes";
        case 1: 
            nombre2 = "diamantes";
        case 2:
            nombre2 = "corazones";
        case 3:
            nombre2 = "picas";
        case 4:
            nombre2 = "espadas";
    }
    if (nombre1 != "\0") {
        strcat(carta, nombre1);
        strcat(carta, " de ");
        strcat(carta, nombre2);
        printf("%s", carta);
    }
    else {
        sprintf(carta, "%s", numero1);
        strcat(carta, " de ");
        strcat(carta, nombre2);
        printf("%s", carta);
    }
    c++;
}
}