PS command on this program - c

Question

In an assignment, I wrote 2 programs that do the same thing, but one of them uses threads. What I'm asked to do is to stop the programs while they are running and use the ps command to compare the two programs, the problem is that I don't know how to do this, I wanted to try stopping the programs using ^z but the programs execute so fast that I can't even do it, is there a way to do what I'm asked to do? is using functions like sleep will help me? or does it affect the results of the ps command?
Here're the programs that I wrote in case it helps and I can modify them to do what I want.
without threads:
#include <stdio.h>
int main(void) {
int mat[100][100]; // Declare the array
// Generate the values for the array
for (int row = 0; row < 100; row++) {
for (int col = 0; col < 100; col++) {
mat[row][col] = row * 5 + col / 3 + col;
}
}
// Sum up the values in the array
int sum = 0;
for (int row = 0; row < 100; row++) {
for (int col = 0; col < 100; col++) {
sum += mat[row][col];
}
}
// Print the result
printf("Sum of all values in mat: %d\n", sum);
return 0;
}
with threads:
#include <stdio.h>
#include <pthread.h>
#define NUM_THREADS 100 // Number of threads (one for each column)
#define ROWS 100 // Number of rows in the array
#define COLS 100 // Number of columns in the array
int mat[ROWS][COLS]; // Array to store the values
int sums[COLS]; // Array to store the sums for each column
// Thread function to sum up a column of the array
void* sum_column(void* arg) {
int col = (int)arg; // Column to sum up
// Sum up the values in the column
int sum = 0;
for (int row = 0; row < ROWS; row++) {
sum += mat[row][col];
}
// Store the result in the sums array
sums[col] = sum;
return NULL;
}
int main(void) {
pthread_t threads[NUM_THREADS]; // Threads
// Generate the values for the array
for (int row = 0; row < ROWS; row++) {
for (int col = 0; col < COLS; col++) {
mat[row][col] = row * 5 + col / 3 + col;
}
}
// Create a thread for each column to sum it up
for (int col = 0; col < COLS; col++) {
pthread_create(&threads[col], NULL, sum_column, (void*)col);
}
// Wait for all threads to finish
for (int col = 0; col < COLS; col++) {
pthread_join(threads[col], NULL);
}
// Sum up the values in the sums array
int sum = 0;
for (int col = 0; col < COLS; col++) {
sum += sums[col];
}
// Print the result
printf("Sum of all values in mat: %d\n", sum);
return 0;
}