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

int main() {
    FILE *fr = fopen("input.wav", "r");

    fseek(fr, 0, SEEK_END);
    long int file_size = ftell(fr);
    fseek(fr, 0, SEEK_CUR);

    char *data = malloc(file_size);
    fread(data, file_size, 1, fr);

    char *startDataBlock = strstr(data, "data");
    unsigned int block_size = *((unsigned int*)(startDataBlock + 4));

    for (int i = 0; i < block_size; i += 2) {
        short value = *((short *) (startDataBlock + 8 + i));

        value *= 1.25;

        *((short *) (startDataBlock + 8 + i)) = value;
    }

    FILE *fw = fopen("output.wav", "wb");

    fwrite(data, file_size, 1, fw);

    fclose(fw);

    fclose(fr);

    return 0;
}