[AYUDA] Programacion en C

void dibuja_piramide(int n){
    for(int j = 0; j<n; j++){
            for(int i = 0; i<j+1; i++){
            printf("*");   
        }
        printf("\n");
    }
}

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

int main(void) {
    char *str; // declare only once, outside the for :)
    for (int i = 0;i < 5; ++i) {
        str = (char *)malloc((i + 2) * sizeof(char)); // reserve memory for the string (i + 1 = number of "*')
        str = (char *)memset(str, '*', i + 1); // set i+1 bytes of "str" to '*'
        write(1, str, i + 1); // print all '*' (write systemcall is better than printf function, because is a systemcall)
        write(1, "\n", 1); // print the new line
        free(str); // allways renember to free the memory :D
    }
    return (0);
}