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What are the bugs in this function?
#include <string.h> #include <stdlib.h> char *reverse(char *input) { int len = strlen(input); char output[len]; for (int i = 0; i < len; i++) { output [len - i - 1] = input[i]; } return output; }
2 Respuestas
+ 5
Rose Candy ,
this looks very much like a homework or something like this. please do a try by yourself first.
thanks for your understanding!
+ 2
Lets look at this:
char *reverse(char *input) {
int len = strlen(input);
char output[len];
for (int i = 0; i < len; i++) {
output [len - i - 1] = input[i];
}
return output;
}
Lets use "Hello" for the input
len now = 5
output = memory-location 1, 2, 3, 4, 5 (named output[0], output[1], ect) probably filled with garbage values
__ __ __ __ __
|__| |__| |__| |__| |__| << 5 memory locations for output
within the scope of the for:
i = 0 initialized; Going to test if i less than 5; then increment i each iteration;
first pass:
output[5 - 0 - 1] (this is equal to 4) becomes input[0]
__ __ __ __ __
|__| |__| |__| |__ | |H |
pass two, three, four and five will result in:
__ __ __ __ __
|o | |l | |l | |e | |H |
You want to end strings with a '\0' terminating char.
1. How will you add that?
2. Your current array cannot handle it