Python GDAL ReadAsArray vs C-GDALR

Question

I am trying to iterate over the values of a raster dataset (band1). I am able to do it in python with the following code snippet (sorry I can't provide the original raster)

import numpy as np
import gdal 

path = "data/Isle_wight.tif"

ds = gdal.Open(path)
myarray = np.array(ds.GetRasterBand(1).ReadAsArray())
print(myarray.shape[0])
#print(columns)
for j in range(myarray.shape[0]-1):
    for i in range(myarray.shape[1]-1):
        print( myarray[j][i])

My goal is to emulate the same in C-GDAL,

here is my code snippet (which does not work)

#include "gdal/gdal.h"
#include "gdal/cpl_conv.h"
int main()
{

    GDALDatasetH raster;
    GDALAllRegister();
    raster = GDALOpen( "/home/roger/Documents/98_GDAL_C++_snippets/data/Isle_wight.tif", GA_ReadOnly);
    if(raster==NULL)
    {
    printf("Invalid Raster Dataset");
    }
    else
    {
    GDALRasterBandH raster_band;
    int XSize, YSize;

    raster_band = GDALGetRasterBand( raster, 1);
    GDALGetBlockSize( raster_band, &XSize, &YSize);
    float *pafScanline;
    int nXSize = GDALGetRasterBandXSize (raster_band);
    int nYSize = GDALGetRasterBandYSize (raster_band);
    pafScanline = (float*) CPLMalloc(sizeof(float)*nXSize);
    int address_of_pafScanline = *pafScanline;
    int band1[nXSize][nYSize];
    int band1 = GDALRasterIO(raster_band, 0, 0,GF_Read, nXSize, 1, pafScanline, nXSize, 1, GDT_Float32, 0, 0);
    for(int i = 0; i <= nXSize; i++) {
        for(int j = 0; j < nYSize; j++ ) {
            printf("%d", band1[i][j]);
        }
    }
}

}

Question: What does GDALRasterIO returns?, I did an array declaration when writing in line 25:

int band1[nXSize][nYSize],

And then I read the raster Data and assign it to the previous band1 array in the following line (26):

int band1 = GDALRasterIO(raster_band, 0, 0,GF_Read, nXSize, 1, pafScanline, nXSize, 1, GDT_Float32, 0, 0);

When compiling through

cc open_array.c -o open_array -lgdal

I got the following error:

open_array.c: In function ‘main’:
open_array.c:26:9: error: conflicting types for ‘band1’
     int band1 = GDALRasterIO(raster_band, 0, 0,GF_Read, nXSize, 1, pafScanline, nXSize, 1, GDT_Float32, 0, 0);
         ^~~~~
open_array.c:25:9: note: previous declaration of ‘band1’ was here
     int band1[nXSize][nYSize];
         ^~~~~
open_array.c:29:31: error: subscripted value is neither array nor pointer nor vector
             printf("%d", band1[i][j]);

Does that happen because of the declaration in line 25?