求一个简单的c语言编程问题?

#include <stdio.h>
#include <iostream.h>
void main()
{
int i=1,j=1,n=0;
for(i=1;i<=9;i++)
{
for(j=1; &&j<=i;j++)
{
printf("%d*%d=%d ",j,i,i*j);
}
printf("\n");
}
}

main()
{ int a, b;
for(a = 1 ;a <= 9 ; a++)
{
for(b = 1; b <= a; b++)
{
printf(\"%dX%d=%2d; \", b,a,a* b);
}
printf(\"\\n\");
}
getchar();
}

=============
1X1= 1;
1X2= 2; 2X2= 4;
1X3= 3; 2X3= 6; 3X3= 9;
1X4= 4; 2X4= 8; 3X4=12; 4X4=16;
1X5= 5; 2X5=10; 3X5=15; 4X5=20; 5X5=25;
1X6= 6; 2X6=12; 3X6=18; 4X6=24; 5X6=30; 6X6=36;
1X7= 7; 2X7=14; 3X7=21; 4X7=28; 5X7=35; 6X7=42; 7X7=49;
1X8= 8; 2X8=16; 3X8=24; 4X8=32; 5X8=40; 6X8=48; 7X8=56; 8X8=64;
1X9= 9; 2X9=18; 3X9=27; 4X9=36; 5X9=45; 6X9