Untitled

#include<conio.h>
#include<stdio.h>


int main()
{
    int n,m;
    printf("Nhap chieu dai m: ");
    scanf("%d",&m);
    printf("Nhap chieu rong n: ");
    scanf("%d",&n);
    for(;n<=0 || m <= 0;)
    {
        if(m <= 0){
            printf("Phai nhap m > 0 \nNhap lai m: ");
            scanf("%d",&m);
        }
        if(n <= 0){
            printf("Phai nhap n > 0 \nNhap lai n: ");
            scanf("%d",&n);
        }
    }
for(int i=1; i<=n; i++) {
        for(int j=1; j<=m; j++) {
            if(i==1||i==n||j==1||j==m) {
                printf("= ");
            } else {printf("  ");}
        }
        printf("\n");
    }
    return 0;
}