Tukukkk

This is the function that captures the string:

void capture(char string) {

    printf("_____________________________________________________________nn");

    printf("Ingrese una cadena: ");

    scanf(" %[^n]s", string);

    printf("Cadena capturada: %sn", string);

    printf("_____________________________________________________________nn");

}

This is the function that is being called in the main function:

    void sort(char string) {  

int opt, i, j, temp = 0;

char string_copy[50];

strcpy(string_copy, string);

for (i = 0; string_copy[i] != ''; i++) 

    for (i = 0; string_copy[i] != ''; i++) {

        for (j = i + 1; string_copy[j] != ''; j++) {

            if (string_copy[i] > string_copy[j]) {

                temp = string_copy[i];

                string_copy[i] = string_copy[j];

                string_copy[j] = temp;

            }

            }

            }



printf("_____________________________________________________________nn");

printf("Ordenar de modo:n1) Ascendenten2) Descendenten");

printf("Seleccione una opcion: ");

fflush(stdin);

scanf(" %d", &opt);

switch(opt) {

    case 1: 

            printf("'%s' ordenado de forma ascendente: %sn", string, string_copy);

            break;

    case 2: 

            printf("'%s' ordenado de forma descendente: ", string);

            for (i=strlen(string); i != 0; i--)

                printf("%c", string_copy[i]);

            printf("n");

            break;

    default: printf("[ ! ] Selección incorrecta!n"); break;

}

printf("_____________________________________________________________nn");

}



//Imprimir la última palabra de la cadena

void last_word(char string[50]) {

    printf("_____________________________________________________________nn");

    int i, count = 0;

    for (i=0; string[i] != ''; i++) {

        if (string[i] == ' ') {

            count = i;

        }

    }

    if (count == 0) {

        printf("Solamente hay una palabra: %sn", string);

    } else {

        printf("La última palabra en '%s' es: ", string);

        for (i=count; string[i] != ''; i++) {

            printf("%c", string[i]);

        }

        printf("n");

    }

    printf("_____________________________________________________________nn");

}

And this is the code that has the problem:

int main() {

int opc = 0;

char string[50];

do {

    printf("MENU:n");

    printf("1) Capturar cadenan");

    printf("2) Sustituir un caracter por otron");

    printf("3) Buscar un caracter e imprimir el número de veces que aparecen");

    printf("4) Buscar un caracter para eliminar de la cadena.n");

    printf("5) Ordenar los caracteres alfabéticamenten");

    printf("6) Imprimir la última palabra de la cadenan");

    printf("0) Salirn");

    printf("Seleccione una opcion: ");

    scanf("%i", &opc);

    printf("Opcion: %d", opc);

    switch(opc) {

        case 1:{

                capture(string);

                break;

        }

        case 2:{

                replace(string);

                break;

        }

        case 3:{

                num_char(string);

                break;

        }

        case 4:{

                delete(string);

                break;

        }

        case 5:{

                sort(string);

                break;

        }

        case 6:{

                last_word(string);

                break;

        }

        case 0:{

                printf("Byen");

                break;

        }

        default: {

                printf("[ ! ] Selección incorrecta!n");

        }

    }

} while (opc != 0);



    return 0;

}

The problem is with option five above in the switch case: It only executes if the captured string does not have any spaces. If you would input "Hello world" for example. Case 5 will never execute and the scanf

printf("Seleccione una opcion: ");

scanf("%i", &opc);

Will just stay there waiting for an input. This only happens, I repeat, if the string captured has spaces AND you choose option five in the switch case.

            capture(&string[50]);

You are passing capture the address of string[50]. But there is no string[50]. So you are passing an address past the end of string to capture. (Since string has fifty entries and 0 is the first, 49 is the last. There is no string[50], it's past the end of the array.

void capture(char string[50]) {

    printf("_____________________________________________________________nn");

    printf("Ingrese una cadena: ");

    scanf(" %[^n]s", string);

    printf("Cadena capturada: %sn", string);

    printf("_____________________________________________________________nn");

}

Ooops, capture writes to the address it was past for string, but that's past the end of the array you allocated. Writing to memory outside the bounds you allocated can trample other variables and cause unpredictable results. Until you fix out of bounds writes, you really can't debug anything else in your program. You can use valgrind or a similar tool to help detect these kinds of errors.

I tried to understand your logic and it seems there is a problem in there:

Why are you passing string[50] to each function? I assume you would like to use the same string variable in every function, so, there's two points for you to check:

1. You should ask for the user to enter the string value before the switch() statement - call capture() in the row before the switch() line, for example. Otherwise, the user could enter other menu options before entering the "capture" function, and, in this case the string will not exist yet, causing a segmentation error - if I'm not mistaken. (Have you tried it? Choosing option 3, for example, before choosing option 1? It must not work)




2. To pass the "string" variable by parameter, use "string", not "string[50]".
   After the declaration (where "50" is the size of the string), the expression "string[50]" represents the 50th value of the string, which doesn't even exist, as pointed in David's answer.