C language programming exercise reference answer chapter 4 (2) Two-dimensional array

/* The maximum absolute value of each line in the 4.16 5*5 matrix, which is exchanged with the diagonal lines of the same row */

# Include "stdio. H"

# Include "math. H"
Void main ()
{
Int A [5] [5] = {1, 3, 4,-5}, {3, 5,-2, 2}, {4, 1, 2, 2 },
{,-, 6}, {, 4 }};
Int I, K, Max, sub, temp;
/* I loop variable, control row, K loop variable, control column, Max current maximum absolute value, sub current maximum absolute value element subscript
Temp temporary variable for exchange */

Printf ("output \ n");/* output */
For (I = 0; I <= 4; I ++)
{
For (k = 0; k <= 4; k ++)
Printf ("% 4D", a [I] [k]);
Printf ("\ n ");
}
/* Switch */
For (I = 0; I <= 4; I ++)
{
/* Assume that the first element is the largest */
Max = FABS (A [I] [0]); sub = 0;
/* Find the element with the largest absolute value and write down the subscript */
For (k = 1; k <= 4; k ++)
{
If (FABS (A [I] [k])> MAX)
{
Max = FABS (A [I] [k]); sub = K;
}
}
/* Switch */
Temp = A [I] [I]; A [I] [I] = A [I] [sub]; A [I] [sub] = temp;
}
/* Output after switching */
Printf ("output \ n" after switching ");
For (I = 0; I <= 4; I ++)
{
For (k = 0; k <= 4; k ++)
Printf ("% 4D", a [I] [k]);
Printf ("\ n ");
}

}

/* 4.17 store any four numbers in a one-dimensional array, such as 5, 1, 8, and 6, and generate the following matrix
5 5 5 5 5 5 5
5 1 1 1 1 5
5 1 8 8 8 1 5
5 1 8 6 8 1 5
5 1 8 8 8 1 5
5 1 1 1 1 5
5 5 5 5 5 5 5
*/
# Include "stdio. H"
# Include "conio. H"
Void main ()
{
Int fournumbers [4], array [7] [7], I, row, column;
Printf ("Enter 4 integers \ n ");
Scanf ("% d", & fournumbers [0], & fournumbers [1], & fournumbers [2], & fournumbers [3]);
For (I = 0; I <= 3; I ++)
{
For (ROW = I; row <= 6-i; row ++)
{
For (column = I; column <= 6-i; column ++)
Array [row] [column] = fournumbers [I];
}
}
/* Output matrix */
For (ROW = 0; row <= 6; row ++)
{
For (column = 0; column <= 6; column ++)
Printf ("% 4D", array [row] [column]);
Printf ("\ n ");
}
Getch ();
}
/* Exercise 4.19 encrypts a line of message. Each letter is converted to the third letter in the alphabet that shifts right, a-d, B-E ,...... z-C */

# Include "stdio. H"
Void main ()
{

Int C;
While (C = getchar ())! = '\ N ')
{
If (C> = 'A' & C <= 'Z') | (C> = 'A' & C <= 'Z '))
{
C = C + 3;
If (C> 'Z' & C <= 'Z' + 3) | C> 'Z ')
C = c-26;

}
Putchar (C );

}
}