C語言打印三角形圖案

1.打印

$
$$
$$$
$$$$
$$$$$
$$$$$$

#include <stdio.h>
int main(void){
	const int ROWS = 6;
	int i,j;
	for (i=0;i<ROWS;i++){
		for (j=0;j<=i;j++){
			printf("$");
		 }	
	printf("\n");
	}
		
	return 0;
}

2.打印

F
FE
FED
FEDC
FEDCB
FEDCBA

#include <stdio.h>
int main(void){
	const int ROWS = 6;
	int i,j;
	int ch;
	for (i=0;i<ROWS;i++){
		for (j='F';j>=('F'-i);j--){
			printf("%c",j);
		 }	
	printf("\n");
	}
		
	return 0;
}

3.打印

A
AB
ABC
ABCD
ABCDE
ABCDEF

#include <stdio.h>
int main(void){
	const int ROWS = 6;
	int i,j;
	int ch;
	for (i=0;i<ROWS;i++){
		for (j='A';j<=('A'+i);j++){
			printf("%c",j);
		 }	
	printf("\n");
	}
		
	return 0;
}

4.打印

A
BC
DEF
GHIJ
KLMNO
PQRSTU

 

#include <stdio.h>
int main(void){
	const int ROWS = 6;
	int i,j;
	int ch='A';
	for (i=0;i<ROWS;i++){
		for (j=0;j<=i;j++){
			printf("%c",ch+j);
		 }	
		 ch++;
	printf("\n");
	}
		
	return 0;
}

5.打印

     A
   ABA
  ABCBA
 ABCDCBA
ABCDEDCBA

#include <stdio.h>
#define N 5

int main(void){
	int i,j,k,l,c;
	int ch='A';
	for(i=0;i<N;i++){
	
		for(j=N;j>i;j--){
			printf(" ");
			
		}
		for(k=ch;k<=i+ch;k++){
			printf("%c",k);
		}	
		for(l=0,c=ch+i-1;l<=i-1;l++,c--){
			printf("%c",c);
		} 
		
		printf("\n");
	}
	return 0;
}