I have the following function:
void InverterString(char *str1){
char aux[strlen(str1)];
for (int c=0; c<5; c++) aux[c] = str1[4 - c];
printf("A string1 invertida fica: %s", aux);
}
However, it prints the phrase that is in printf , but does not print the string. Why?
Thank you.
For me, InverterString("abcde"); produced as edcba response. See here at ideone.
However, because of the numbers 5 and 4 in the code, this only works for strings of size 5. Any strings bigger or smaller, this will go wrong. To solve this, you already have strlen , so just use it to find the appropriate string size. Just replace 5 with string size and 4 with string length minus 1:
#include <stdio.h>
void InverterString(char *str1) {
int tamanho = strlen(str1);
char aux[tamanho + 1];
for (int c = 0; c < tamanho; c++) {
aux[c] = str1[tamanho - c - 1];
}
aux[tamanho] = 0;
printf("A string1 invertida fica: %s", aux);
}
int main(void) {
InverterString("O rato roeu a roupa do rei de Roma e a rainha roeu o resto.");
return 0;
}
Here's the output:
A string1 invertida fica: .otser o ueor ahniar a e amoR ed ier od apuor a ueor otar O
Oh, and notice that you need to explicitly put the null terminator (0) also in aux .
It's more elegant and functional that you create a variable and assign it the size of your input string, so it will work for any string size. Also, trying to modify your code minimally, I made the change and included the string.h library and looked like this:
#include <stdio.h>
#include <string.h>
void InverterString(char *str1){
int tamanho=strlen(str1);
char aux[tamanho];
for (int c=0; c<tamanho; c++) aux[c] = str1[(tamanho-1)-c];
printf("A string1 invertida fica: %s", aux);
}
int main(void) {
InverterString("Olá Danny!");
return 0;
}