How to determine the minimum value and the maximum value in a matrix of integers with c++

Exercise: An matrix of size 5 x 5 contains integers. Write a program in C++ that determines the minimum and the maximum of the values contained in the Matrix. Print out the contents of the matrix, marking the minimum values with the sign - and maximum values with the sign +

#include <iostream>

int main ()
{  
    // Initialize random number generator
    srand(time(NULL));
    
    // Define the dimension of the matrix
    const int R = 5;
    const int C = 5;
    
    // Declare a matrix and a vector
    int m [R][C];
    
    // Fill the matrix with random values from 1 to 50
    for(int i=0; i<R; i++)
    {
        for(int j=0; j<C; j++)
        { 
        m[i][j] = (rand()%90)+10;
        }
    }
    
    // Calculating the minimum and maximum of the matrix 
   int min = 100;
   int max = 0;

    for(int i=0; i<R; i++)
    {
        for(int j=0; j<C; j++)
        {
         if (m[i][j] < min) 
            min = m[i][j];
         if (m[i][j] > max) 
            max = m[i][j];
        }
    }
    
    // Showing the contents of the matrix
	// Marking the minimum values with the sign -
	// Marking the maximum values with the sign +
    for(int i=0; i<R; i++)
    {
        for(int j=0; j<C; j++)
        {
       		if(m[i][j]==min)
            	printf( "%d-\t", m[i][j]);
			else if(m[i][j]==max)
				printf( "%d+\t", m[i][j]);
			else
				printf( "%d\t", m[i][j]);
        }
        printf( "\n");
    }
        
    return 0;
}

This is the result:

90    65    45    43    45   
10-   52    95    21    87   
84    95    94    19    79   
35    35    55    87    12   
65    25    98+  31    58