How to delete string element from 3d array in c

  c++, multidimensional-array, sorting

I want to delete complete row in this 3d array specific of my choice by just using name or [x][0] element , but how?

char arr[4][6][20] = {
// c is the element i want to delete
// i am using this procedure to delete the row
for(c = 1; c < 4 - 1; ++c){
    for(z = 0;z < 6;++z){
        arr[c][z][20] = arr[c+1][z];

Source: Windows Questions C++