2d array dynamic memory allocation in c code example

Example 1: array 2d dynamic allocation c++

int** a = new int*[rowCount];
for(int i = 0; i < rowCount; ++i)
    a[i] = new int[colCount];

Example 2: double pointer malloc in c

char *x;  // Memory locations pointed to by x contain 'char'
char **y; // Memory locations pointed to by y contain 'char*'

x = (char*)malloc(sizeof(char) * 100);   // 100 'char'
y = (char**)malloc(sizeof(char*) * 100); // 100 'char*'

// below is incorrect:
y = (char**)malloc(sizeof(char) * 50 * 50);
// 2500 'char' not 50 'char*' pointing to 50 'char'