Write a c program to generate all combinations of 1, 2 and 3 using for loop.

Here’s a C program that uses nested for loops to generate all combinations of 1, 2, and 3:

#include <stdio.h>

int main() {
    int i, j, k;
    for (i = 1; i <= 3; i++) {
        for (j = 1; j <= 3; j++) {
            for (k = 1; k <= 3; k++) {
                printf("%d %d %d\n", i, j, k);
            }
        }
    }
    return 0;
}

Output:

1 1 1
1 1 2
1 1 3
1 2 1
1 2 2
1 2 3
1 3 1
1 3 2
1 3 3
2 1 1
2 1 2
2 1 3
2 2 1
2 2 2
2 2 3
2 3 1
2 3 2
2 3 3
3 1 1
3 1 2
3 1 3
3 2 1
3 2 2
3 2 3
3 3 1
3 3 2
3 3 3

In this program, we use three nested for loops, with each loop iterating over the numbers 1, 2, and 3. Inside the innermost loop, we print out the current combination of numbers using printf(). This generates all possible combinations of the numbers 1, 2, and 3.