Question

This code compiles fine but give segmentation fault error while running? Can anyone tell why?

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

int main() {
    const char s2[] = "asdfasdf";
    char* s1;

    strcpy(s1, s2);
    printf("%s", s1);

    return 0;
}

Answer 1

You allocated space for a single pointer, s1, but not the bytes pointed at by s1.

A solution is to dynamically allocate memory for s1:

s1 = (char *)malloc(strlen(s2) + 1);
strcpy(s1, s2);

Keep in mind that you need to allocate one more byte of memory (the +1 in the call to malloc) than the number of characters in s2 because there is an implicit NULL byte at the end.

See C Memory Management (Stack Overflow) for more information.