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



//Função verifica se o caracter é ou não uma vogal
int eh_vogal(char letra)
{
if (letra == 'a' || letra == 'A' ||
letra == 'e' || letra == 'E' ||
letra == 'i' || letra == 'I' ||
letra == 'o' || letra == 'O' ||
letra == 'u' || letra == 'U')
return 1;
else
return 0;
}

int main() 
{

char frase[21], vogalInicio[7], vogalFinal[7];
int tamFrase;



printf("\n\nEscreva uma frase: ");
gets(frase);

tamFrase = strlen(frase);


int cont = 0;
for (int i = 0; (cont < 5) && (i < tamFrase); i++)
{
if (eh_vogal(frase[i]) == 1)
{
vogalInicio[cont] = frase[i];
cont++;
}
}
vogalInicio[cont] = '\0';

cont = 0;
for (int i = tamFrase; (cont < 5) && (i >= 0); i--)
{
if (eh_vogal(frase[i]) == 1)
{
vogalFinal[cont] = frase[i];
cont++;
}
}
vogalFinal[cont] = '\0';


printf("\n\n\n Vogais no inicio da frase %s: ", frase);
for (int i = 0; vogalInicio[i] != NULL; i++)
printf("%c ", vogalInicio[i]);

printf("\n\n\n Vogais no final da frase %s: ", frase);
for (int i = 0; vogalFinal[i] != NULL; i++)
printf("%c ", vogalFinal[i]);
printf("\n\n");

system("PAUSE");
return (0);
}

In function 'main':
Line 35: error: 'for' loop initial declaration used outside C99 mode
Line 46: error: redefinition of 'i'
Line 35: error: previous definition of 'i' was here
Line 46: error: 'for' loop initial declaration used outside C99 mode
Line 58: error: redefinition of 'i'
Line 46: error: previous definition of 'i' was here
Line 58: error: 'for' loop initial declaration used outside C99 mode
Line 58: warning: comparison between pointer and integer
Line 62: error: redefinition of 'i'
Line 58: error: previous definition of 'i' was here
Line 62: error: 'for' loop initial declaration used outside C99 mode
Line 62: warning: comparison between pointer and integer