check type expressions and produce type.txt

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef enum {
    TYPE_INT,
    TYPE_FLOAT,
    TYPE_BOOL,
    TYPE_ERROR
} Type;

typedef struct {
    Type type;
    union {
        int i;
        float f;
        int b;
    } value;
} Expr;

typedef struct {
    Type left;
    Type right;
} Assignment;

Assignment assignments[100];
int num_assignments = 0;

void check_type(Expr* expr) {
    if (expr->type == TYPE_ERROR) {
        return;
    }
    if (expr->type == TYPE_INT || expr->type == TYPE_FLOAT || expr->type == TYPE_BOOL) {
        return;
    }
    printf("Error: Unknown type %d\n", expr->type);
    expr->type = TYPE_ERROR;
}

void check_assignment(Expr* left, Expr* right) {
    if (left->type == TYPE_ERROR || right->type == TYPE_ERROR) {
        return;
    }
    if (left->type == right->type) {
        assignments[num_assignments].left = left->type;
        assignments[num_assignments].right = right->type;
        num_assignments++;
        return;
    }
    printf("Error: Incompatible types %d and %d in assignment\n", left->type, right->type);
    left->type = TYPE_ERROR;
}

int main() {
    Expr a = { TYPE_INT, .value.i = 5 };
    Expr b = { TYPE_FLOAT, .value.f = 3.14 };
    Expr c = { TYPE_BOOL, .value.b = 1 };
    Expr d = { TYPE_ERROR };

    check_type(&a);
    check_type(&b);
    check_type(&c);
    check_type(&d);

    check_assignment(&a, &b);
    check_assignment(&b, &c);
    check_assignment(&c, &d);
    check_assignment(&a, &a);

    printf("Assignments:\n");
    int i;
    for(i = 0; i < num_assignments; i++) {
        printf("%d = %d\n", assignments[i].left, assignments[i].right);
    }

    return 0;
}