c - Placing an integer unto a two dimension array (matrix) -

ok, guys i'm trying make program in guess inputted number placed randomly unto matrix or 2 dimensional array. example user inputted '3' , integer placed on random row , column of matrix.

#include<stdio.h> #include<conio.h> #include<stdlib.h>  #define r 4 #define c 4 void display(char a[][c]); void placing(char b[][c]); void guess(int m, int n);  void main(){ int x=0,y=0,m,n,number; int matrix[r][c]; char a[r][c]={{'x','x','x','x'},{'x','x','x','x'},{'x','x','x','x'},{'x','x','x','x'}}; printf("\t\t\t      welcome game"); printf("\nenter number: "); scanf("%d",&number); display(a); placing(a); printf("\n\nyour number being placed @ random location"); printf("\n\nguess number located (row) (column)"); printf("\n\nenter coordinates: "); scanf("%d%d",&m,&n);  getch(); }  void display(char a[][c]){ for(int row=0; row<r; row++) {     printf ("\n");     for(int column=0; column<c; column++)     {     printf ("\t%c\t", a[row][column]);     } } }  void placing(int b[][c]){ int randomrow=0,randomcolumn=0; int i=0;  randomrow = rand()%4; randomcolumn = rand()%4;  for(int row=0; row < randomrow; row++){     for(int column=0;column < randomcolumn; column++, i++){         b[row][column];     } } printf("%d",b[r][c]); } 

this whole program. tips?

#include <stdio.h> #include <stdlib.h> #include <time.h>  int main() {     int matrix[4][4] =      {         {-1,-1,-1,-1},         {-1,-1,-1,-1},         {-1,-1,-1,-1},         {-1,-1,-1,-1},     };      int user_input;     int random_row;     int random_column;     int row_guess;     int col_guess;      printf("enter number add: \n");     scanf("%d", &user_input);     printf("user entered: %d\n", user_input);      srand(time(null));       random_row = rand() % 4;     random_column = rand() % 4;      printf("random_row: %d\n", random_row);     printf("random_column: %d\n", random_column);      matrix[random_row][random_column] = user_input;      for(int row = 0; row < 4; row++)     {         for(int column = 0; column < 4; column++)         {             printf("%d ", matrix[row][column]);         }         printf("\n");     }      printf("guess random row: \n");     scanf("%d", &row_guess);     printf("user row guess: %d\n", row_guess);      printf("guess random column: \n");      scanf("%d", &col_guess);     printf("user column guess: %d\n", col_guess);      if (matrix[row_guess][col_guess] == user_input)     {         printf("you guessed correctly!\n");     }     else     {         printf("you guessed incorrectly\n");     }      return 0; }